The first-past-the-post voting system – plurality voting in single-member districts – had two widely perceived advantages. First, it was easy to understand how a winner was chosen – the successful candidate simply had to have more votes than any other candidate. The winner did not have to have an absolute majority (50% plus one) of the votes. Second, under this system it was likely that one party would receive an absolute majority of the seats in the House of Representatives.
Until the late 19th century New Zealand’s Parliament didn’t have formal political parties. However, parties dominated Parliament from 1890 onwards. The first party to be in government, the Liberal Party, won more than 50% of the votes – as well as an absolute majority of the seats in Parliament – in 1890, 1893, 1899, 1902 and 1905. (In 1896 it won 46% of the votes, but more than half the seats.)
By 1905 New Zealand’s parliamentary electoral system was based solely on single-member districts. The City Single Electorates Act 1903 abolished the last four multi-member seats, and for the next 90 years each voter had only one vote in each election – for one candidate in their electorate.
After 1906 the formerly monolithic Liberal Party looked somewhat shaky. The party had been in power for 15 years and following the death of Premier Richard Seddon there were party discipline problems, partly manifested in a scourge of surplus candidates all claiming to be Liberals of one type or another standing for election to Parliament. In 1907–8 the Liberals were defeated in two by-elections by candidates who received less than 50% of the votes cast. The new Liberal leader, Joseph Ward, resurrected an idea Seddon had promoted without success – replacing New Zealand’s first-past-the-post voting system with a two-round electoral system, also known as a second-ballot system.
In order to be elected under this system, a candidate had to have an absolute majority of the votes cast. If no candidate won more than half the votes, then a run-off election between the two leading candidates – a second ballot – was held a short while later. The two-round system was used for two parliamentary general elections – in 1908 and 1911 (and for by-elections held between 1908 and 1913) – before being abolished.