In the post-Second World War period in New Zealand, under the first-past-the-post electoral system, the level of disproportionality was 11%. This is a measure of the disparity between the share of seats won by political parties and the share of votes they received. The New Zealand figure was high by international standards.
More British than Britain
A major analysis of the world’s electoral systems, Rein Taagepera and Matthew Soberg Shugart’s Seats and votes, noted in 1989 that ‘New Zealand is in some ways more British than Britain in its adherence to single-seat plurality elections and the two-party system that often goes with them.’1 Since the adoption of the German system of MMP, no one has suggested that New Zealand has become more German than Germany.
Proportionality under MMP
In contrast, the disproportionality figure for New Zealand under the mixed-member proportional (MMP) system has been far lower. In the six MMP elections up to 2011, the degree of disproportionality averaged less than 3%.
In the first eight MMP elections in New Zealand to 2017, no single party won more than half the seats in Parliament. All the governments formed under MMP since 1996 had been coalition governments – more often than not, minority governments (with less than 50% of the seats in Parliament). At the same time, however, every MMP government in New Zealand was led by one of the two major parties: National (1996–99 and 2008–17) and Labour (1999–2008, 2017–). In 2020, Labour won 65 of the 120 seats and could have governed alone, but chose to give the Green Party co-leaders ministerial positions.
Kicking the tyres
In mid-2008 John Key, the leader of the National Party (then in opposition), promised that the party would ‘open our ears to New Zealanders’ views on their voting system. New Zealanders have had to wait long enough for a chance to kick the tyres on MMP.’2
While New Zealand governments have not been quite as strong under MMP as they were in the first-past-the-post era, they have not been at all unstable.
The National-led government formed in 2008 had a policy to give New Zealanders an opportunity to review the voting system. As a result, on 26 November 2011 New Zealand held its third referendum on voting systems. As in 1992, the referendum posed two questions:
Should New Zealand keep the Mixed Member Proportional (MMP) voting system?
If New Zealand were to change to another voting system, which system would you choose?
The first of four options following the second question was the first-past-the-post voting system, which New Zealand had until 1996.
All of the voting systems on offer in the 2011 referendum had overseas precedents. MMP originated in Germany. Preferential voting is used for the Australian House of Representatives. Single transferable voting is used to elect the lower house of the Irish Parliament. The supplementary member system is used for both houses of the Japanese Parliament. First-past-the-post is used to elect MPs to the British House of Commons.
The other three options had also been on the voting paper in the 1992 referendum. They were:
- preferential voting
- single transferable vote
- supplementary member.
Nearly 58% of those who voted in the November 2011 referendum cast a valid vote in favour of keeping MMP. Unlike in 1992, this meant there was no follow-up referendum. New Zealanders had effectively endorsed the proportional representation system for parliamentary elections.