What is New Zealand's MMP electoral system and does it favour coalitions?

WELLINGTON – New Zealand Prime Minister Christopher Luxon said this week he was open to a referendum on the country's electoral system, sparking vigorous debate, with critics saying any such move would be seen as a “power grab” by the larger parties.

New Zealand currently has a mixed-member proportional (MMP) system, which has made coalitions the norm since it was introduced three decades ago.

Why MMP?

New Zealand switched from a British first-past-the-post system, in which the top finisher in each electoral district wins the seat, to MMP on the recommendation of a commission addressing concerns that smaller parties were being left out.

All governments under MMP have been coalitions of the centre-left Labour or centre-right National with the support of smaller parties, except in 2020 when the Labour government swept to power after successfully managing the early months of the COVID-19 outbreak. Originating in Germany, MMP has been adopted, sometimes with modifications, in countries including Bolivia, Lesotho, South Korea and Thailand.

How it works

Under MMP, voters cast two votes: one for their preferred constituency candidate and one for a party. The candidate with the most votes wins and becomes an MP, while the party vote decides how many seats each party gets in parliament.

The winning candidates of the country's 71 constituencies take their seats automatically, while the remaining seats are filled from party lists, allocated to match each party’s share of the nationwide vote. A party or bloc can form a government when it secures a majority in the single-chamber parliament, usually at least 61 of 120 seats.

There are expected to be about 49 list seats in this election, though that number can change.

Political parties must get at least 5 per cent of the party vote or win at least one electorate seat to get any seats in Parliament.

Parliament normally has 120 seats, but extra seats can be added when a party wins more electorate seats than its share of the nationwide party vote would otherwise entitle it to. This happened after the 2023 election, when Te Pati Māora won six electorates while receiving 3.1 per cent of the party vote. Polls indicate this could happen again in 2026.

In the system, seven of the electorate seats are Maori electorates, reserved for voters who choose to enrol on the Maori electoral roll. Maori voters may instead choose to enrol in a general electorate.

Quirks

Since MMP was first used in New Zealand in 1996, minor parties have often played a decisive role in the formation of the government.

New Zealand First has been the most prominent kingmaker, backing National after the 1996 election and Labour after the 2017 election. Te Pati Maori has also helped larger parties govern, supporting National-led governments after the 2008, 2011 and 2014 elections.

At this election, the centrist Opportunity Party could also become pivotal if it reaches the 5 per cent party-vote threshold or wins an electorate seat.

The 2017 election showed how the largest party does not always end up in power. National won 56 seats, more than Labour's 46, but was unable to assemble a majority. Labour formed a government through a coalition with New Zealand First and a confidence-and-supply agreement with the Green Party. REUTERS