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International law

by K. J. Keith

New Zealand, like other countries, is bound by international law. The country has been an active participant in the organisations that make international law, such as the United Nations. It has also used international law to defend its own interests, for example regarding trade with Australia or against French nuclear testing in the Pacific.


What is international law?

International law deals with relationships that go beyond the borders of any one country. International laws and institutions are used in situations such as:

  • dealing with crimes committed across or beyond borders, for instance a murder on board a ship in international waters
  • regulating international travel by sea or air, or across international land borders
  • deciding on the rights different countries have to tax income from international transactions
  • dealing with allegations that a parent has breached custody rights by abducting a child from one country to another
  • regulating contracts for the sale of goods and services between countries, such as in the sale of New Zealand dairy products to China
  • dealing with pollution from a foreign source, such as the impact on a coast by an oil spill from a foreign-flagged vessel operating in international waters.

There are also many circumstances that arise from the very existence of almost 200 countries across the world and from the relations between them. Over centuries law has been developed to deal with all of these situations through practice (known as customary international law), agreements (known generically as treaties), general principles of law, court decisions and scholarly writing.

The functions of international law

The functions of many rules of international law are essentially the same as those of national law. They may:

  • establish constitutions of international organisations, such as the Charter of the United Nations
  • be equated to legislation (written law), such as the United Nations Convention on the Law of the Sea or The Hague Convention on the Civil Aspects of International Child Abduction
  • determine boundaries between nations
  • be bilateral contracts involving a mutual exchange of promises, such as the contracts about air services between different states, of which New Zealand has about 40.

Areas covered by international law

The subject matter of international law is extensive and growing as its emphasis moves from the coexistence of states to cooperation between them. Some parts of international law are so integrated into national law that they have become indistinguishable.

Among the many areas covered by international law are:

  • regulating when armed force can be used by states and setting the rules for armed conflicts
  • disarmament and arms control
  • aspects of statehood, including recognition of states, their territory and their diplomatic relations
  • how states can acquire land and maritime areas
  • international trade, finance and commerce
  • international communications
  • international spaces (sea, air, outer space, arctic areas, rivers and canals)
  • the environment
  • labour relations and human rights.

Who is subject to international law?

State-to-state relationships

Some of the rules of international law govern the relations between states. Such rules have been applied to disputes between New Zealand and Japan over the definition of maritime areas and the exploitation of marine resources. Japan objected to New Zealand’s extension of fisheries limits to 12 nautical miles (22 kilometres) in the 1960s and then to 200 nautical miles (370 kilometres) in the 1970s. These disputes were settled under international law, but such settlements do more than simply define the rights of New Zealand and Japan as nations. Settlements like these also define the rights of individuals and companies to catch and consume fish. The controls established also help determine whether fish populations will be sustainable in the future.

The state and individuals

Other rules apply to the relations between states and their citizens and residents. International agreements impose certain obligations on states regarding their treatment of residents. For example, under the International Covenant on Civil and Political Rights, a state must accord a fair trial to those individuals appearing in its courts. The right to a fair trial is incorporated in New Zealand legislation (written law), including the New Zealand Bill of Rights, and by many years of court rulings (precedent). International law also imposes obligations on individuals not to commit crimes of an international character, such as torture, war crimes and slavery. International law contains provisions for prosecution and extradition for crimes of this nature.

Relations between individuals

International law also covers relations between individuals.

New Zealand is party to more than 60 international labour conventions which primarily operate between employers and employees. Some, for instance, fix hours of work, holidays and minimum age of employment. Others provide for workers’ compensation and freedom of association, and prohibit forced labour and discrimination in employment.

Human rights treaties regulate both relations between the state and the individuals, and relations between individuals themselves. New Zealand is a party to almost all of the principal conventions adopted within the United Nations since 1965.

Family law conventions, which regulate adoption, child abduction and recovery of family support, operate internationally.

The rights and duties of individuals or companies in international commerce and transport agreements are often determined by treaties. New Zealand is party to the United Nations Convention on the International Sale of Goods and to conventions for the recognition and enforcement of awards made through arbitration (where disputes are decided by an arbitrator). The country has also signed up to conventions on collisions and salvage, carriage by air, and bills of lading (detailed lists of goods shipped). Bodies such as the International Chamber of Commerce facilitate international trade treaty negotiations by preparing standard form agreements.


New Zealand and international law: a brief history

New Zealand became increasingly involved in developing and applying international law as the country took a more prominent place on the international stage. New Zealand joined the International Telegraph Union (the oldest universal international organisation), as early as 1875, followed by the Universal Postal Union in 1892. These two organisations grew out of the need for international regulation and organisation of communications systems.

New Zealand’s treaty with Sweden

Apart from the Treaty of Waitangi, New Zealand’s treaty list began with the Treaty of Peace and Commerce, originally signed by the United Kingdom and the Kingdom of Sweden in 1654. As a British colony, New Zealand was considered bound by this treaty with Sweden from the date of colonisation in 1840. New Zealand withdrew from the Treaty of Peace and Commerce in 1933, although it remained in force for the United Kingdom.

League of Nations, 1919 to 1939

In 1919 New Zealand became an original member of the League of Nations, set up under the Treaty of Versailles at the end of the First World War. From 1920 New Zealand had international responsibilities for Western Samoa under a league mandate. These responsibilities continued under a United Nations Trusteeship Agreement from 1946 until Western Samoa became independent in 1962. New Zealand emphasised the principle of collective responsibility at the League of Nations, notably in opposition to Italy’s 1935 invasion of Abyssinia (Ethopia) and in supporting a peaceful resolution to the Spanish Civil War (1936–39). The League of Nations effectively ceased to function with the outbreak of the Second World War in 1939.

International Labour Organization

New Zealand has been a member of the International Labour Organization (ILO) since it was founded in 1919, although it only became active in the ILO from 1935. Between 1938 and 2003 New Zealand ratified 52 international labour conventions produced by the ILO. These have included conventions on unemployment, forced labour, the 40-hour working week, working conditions of seamen, contracts of employment, paid holidays and rights of organisation.

The changing UN

The United Nations and its agencies have had to constantly adapt in response to a changing world. The United Nations began in 1945 with 51 members, including only three from Africa, one from South Asia, one from South-East Asia, two from the Caribbean and no Pacific countries other than Australia and New Zealand. By 2012 there were 193 member nations of the UN. This increase was the result of the decolonisation of Africa, Asia, the Caribbean and the Pacific, and by the break up of the Soviet Union and Yugoslavia in the 1990s.

United Nations

New Zealand’s involvement with international law increased greatly from the end of the Second World War with the establishment of the United Nations. A range of international agencies were established from the 1940s onwards that are involved with issues of international concern, such as health, food and agriculture, education, science and culture, civil aviation, maritime matters, monetary and development banking matters, trade, meteorology and refugees.

The Cold War and nuclear weapons

From 1945 to 1991 the rivalry between the Soviet Union and the United States, the United Kingdom and France was reflected in the Cold War, a period of fluctuating military and political tensions. This competition between the nuclear superpowers heightened the need to control atomic weapons. The International Atomic Energy Agency was established in 1957, with New Zealand as a founding member. New Zealand was also one of the first signatories to the Partial Test Ban Treaty in 1963 and to the Treaty on the Non-Proliferation of Nuclear Weapons in 1968.

France moved its nuclear testing to its territories in the South Pacific in 1963. New Zealand responded by issuing a series of protest notes and, in 1973, sent two naval frigates to join private vessels protesting in the nuclear-testing zone. That same year the New Zealand and Australian governments brought legal proceedings against France in the International Court of Justice in The Hague, seeking to have the atmospheric tests declared illegal. New Zealand revived its claim against France in 1995, challenging the French decision to resume underground nuclear tests. The French ceased nuclear testing in 1996.

Through the 1970s New Zealand played a prominent role, with newly independent Pacific states and Australia, in establishing the South Pacific Nuclear Free Zone. In 1985 New Zealand declared itself nuclear free by banning nuclear-armed and nuclear-propelled ships from its ports.

Changing trade relationships

New Zealand’s first post-war trade agreements were with former enemy states: Japan in 1958 and the Federal Republic of Germany (West Germany) in 1959. New Zealand’s trade relations underwent major changes from the 1960s onwards. New markets were opening up, and the United Kingdom, traditionally New Zealand’s major export market, was indicating its intention to join the European Economic Community (later the EU).

As its manufacturing developed, New Zealand entered into a limited free-trade agreement with Australia in 1965, followed 15 years later by the Closer Economic Relations (CER) agreement. The rapid development of New Zealand trade with East Asia was marked by the formation of APEC (Asia–Pacific Economic Cooperation) in 1989, and by free-trade agreements with a range of Asian nations. These included an agreement for the promotion and protection of international investment with the Peoples’ Republic of China in 1988, followed by a free-trade agreement in 2008. These were the first such agreements China made with an OECD country. Trade agreements are now made in the context of the World Trade Organization (WTO) system, which developed from the General Agreement on Tariffs and Trade (GATT) of 1948. The WTO, established in 1994, tries to enable international trade to flow as smoothly, predictably and freely as possible. New Zealand joined the WTO in 1995.


International law on human rights and conflict

A large body of international law has been created through the many treaties between nations and a range of international institutions. However, despite the existence of the law on paper, in the 2000s the international community still faces many challenges in establishing compliance in practice. The difficulties involved can be seen in the attempts to protect human rights in times of peace and during armed conflict.

Cluster munitions and disability rights

In 2009 New Zealand enacted the United Nations Convention on Cluster Munitions (CCM), which bans the use of cluster munitions – weapons that release large numbers of smaller explosives, and which pose a particular threat to civilians. The CCM bans the use of cluster munitions in warfare and also seeks to assist the victims of these weapons, recognising states’ obligations under the Convention on the Rights of Persons with Disabilities. New Zealand enacted the disability convention in 2008, guaranteeing the human rights and fundamental freedoms of people with disabilities.

Geneva Conventions and armed conflict

The Geneva Conventions of 1864 (updated in 1906, 1929 and 1949) are rules that apply in times of armed conflict to protect those who are not taking part in hostilities. As well as civilians, this includes combatants who, due to sickness or wounds, are no longer able to fight. New Zealand is a party to the Geneva Conventions, which aim to balance the principle of protection against the military necessities of war. Over recent decades the international community has placed major emphasis on the better implementation of the conventions, but with limited and uneven success.

Among the measures intended to be implemented by the Geneva Conventions are:

  • the training of military, and other personnel involved in war, in the day-to-day application of the conventions and rules
  • the work of the International Committee of the Red Cross
  • national disciplinary action and criminal prosecution over war crimes
  • international criminal proceedings over war crimes, as occurred in Nuremberg and Tokyo after the Second World War, for former Yugoslavia, Rwanda, Cambodia and Sierra Leone in the later 20th century, and the proceedings at the International Criminal Court
  • various forms of international inquiry.

Interstate claims arising from the wars in former Yugoslavia, central Africa, and Ethiopia and Eritrea have also been decided by the International Court of Justice and a bilateral claims commission.

Human rights in peace time

In many parts of the world the means for the application and enforcement of international human rights law in times of peace are much better established than those for times of war. Domestic laws on human rights, as applied day-to-day by police, courts and other authorities, often have their origins in international law. The international sources can include law contained in major human rights treaties and labour conventions. Over the years international mechanisms have been set up to try to enable the human rights law from such treaties and conventions to govern the cross border interactions of people.

International courts

A number of international courts deal with international disputes including issues of armed conflict:

  • The International Court of Justice (ICJ), set up in 1946, is the principal judicial organ of the United Nations (UN). It is a world court responsible for settling legal disputes submitted to it by states. New Zealand has made a declaration accepting the jurisdiction of the ICJ as compulsory. In 2005 New Zealander Kenneth Keith was elected by the UN General Assembly and the Security Council to serve a nine-year term as a judge of the ICJ.
  • The International Criminal Court (ICC) was set up in 2002 as a permanent court. It was created to try individuals accused of serious crimes such as genocide, crimes against humanity and war crimes in cases where states are unable or unwilling to do so. New Zealand was involved in the negotiations to set up the ICC and has continued to support it.
  • A number of international criminal tribunals have been set up to deal with specific acts of genocide or crimes against humanity, including tribunals or special courts for the former Yugoslavia, Rwanda, Lebanon, Cambodia and Sierra Leone. New Zealander Silvia Cartwright served as a judge on the Extraordinary Chambers of the Courts of Cambodia (from 2006), while David Baragwanath served as a judge on the Special Tribunal for Lebanon (from 2010).

International law on travel, trade and resources

A large body of international law covers the movement of people and goods between countries. Laws concerning people cover both the rights of travellers and the rights of nations to restrict entry. There are laws covering the transport and trade in goods, along with laws, such as the law of the sea, that cover the rights to resources outside national borders.

Laws governing international travel and immigration

The international law governing the movement of people, goods, aircraft and ships across borders is applied every day around the world by immigration, customs, agriculture, aviation and port authorities. Sometimes disputes will arise, for instance over those seeking refugee status, fearing persecution, death or torture. Those issues were addressed by the New Zealand authorities and courts in the case of asylum-seeker Ahmed Zaoui in 2004–5. The courts apply the presumption that New Zealand legislation must be read consistently, if possible, with international law. In the Zaoui case the relevant New Zealand law was the Immigration Act and the relevant international law was the Refugees Convention, the International Covenant on Civil and Political Rights and the Convention against Torture. The New Zealand courts, after consideration, ruled essentially in favour of Zaoui.

Laws governing international trade

The World Trade Organization (WTO) has set up a binding disputes settlement procedure to deal with trade disputes between its members. Among the issues covered are:

  • trade and tariffs
  • agriculture, including subsidies
  • health and sanitation, including animal and plant disease
  • rules to determine the origin of a product
  • import licensing and customs valuation
  • intellectual property.
  • Consultations – the countries involved meet to resolve the dispute.
  • Panel stage – if consultation has not resolved the issue, the country laying the complaint can call for an adjudicative panel to be set up. If the panel decides there has been a breach of the relevant WTO agreement, it can call on the offending country to change its laws or policies to rectify this.
  • Appeal – either party in a dispute has the right of appeal to the WTO Appellate Body, a panel of seven members who serve four-year terms. New Zealander Chris Beeby was appointed an initial member of the Appellate Body when it was established in 1995.

The WTO has a three-stage settlement process:

Disputes between foreign investors and host states are also increasingly becoming the subject of binding arbitration.

Anzac apples

Australia had banned the importation of New Zealand apples for many years on the grounds that the bacterial disease fire blight, present in New Zealand apples, should be kept out of Australia. New Zealand exporters argued the disease could not be carried on mature fruit. After going before a WTO panel, both New Zealand and Australia took the dispute to the WTO Appellate Body. The Appellate Body resolved the dispute in October 2010, deciding in favour of New Zealand’s apple exporters.

The law of the sea

The law of the sea is a part of the international law regulating the environment. This law has been the subject of major change over the centuries and particularly since the mid-20th century. In some areas it is still seriously incomplete, particularly in protecting highly migratory fish stocks in the high seas (the parts of oceans outside of any nation’s territorial waters). New Zealand played a major role in developing the Convention on the Conservation and Management of the High Seas Fishery Resources of the South Pacific Ocean, an example of ongoing lawmaking. The enforcement of the law on the high seas is primarily a responsibility of the flag state – the state in which a ship is registered. The use of flags of convenience, where the ship is registered in a different country to that of its owners, can make it difficult to enforce the law of the sea. In some cases coastal states exercise authority over a 200-nautical-mile exclusive economic zone, and port states may have particular powers and responsibilities, generally exercised through their own government authorities.

Southern bluefin tuna

In 1999 Japan announced that it would carry out an experimental fishing programme for southern bluefin tuna, in addition to its existing commercial catch. New Zealand and Australia objected to the proposed increase in the Japanese catch, submitting the case to international arbitration. In the meantime the International Tribunal on the Law of the Sea called a halt to the Japanese experimental fishing programme until issues were dealt with. The dispute was eventually resolved by negotiations between New Zealand, Australia and Japan.

The International Tribunal for the Law of the Sea is the tribunal that makes decisions on disputes arising from the application of law of the sea. It deals with cases involving the detention of vessels or crews, as well as disputes over the seabed, fisheries and the marine environment. Maritime disputes are also the subjects of binding third-party settlements by the International Court of Justice or by ad hoc arbitration tribunals, notably to resolve maritime boundaries in many parts of the world.


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How to cite this page: K. J. Keith, 'International law', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/mi/international-law/print (accessed 22 November 2019)

He kōrero nā K. J. Keith, i tāngia i te 20 Jun 2012