How New Zealand's MMP Voting System Decides Governments

When New Zealanders vote on Saturday, they will use a system that rarely hands one party an outright majority. It is called mixed member proportional representation, or MMP, and it shapes almost every part of the country's politics.

Every voter has two votes. The first is for a local electorate candidate, and the person with the most votes in each electorate wins that seat. The second is the party vote, which decides how many seats each party receives in total in proportion to its national support. The party vote is the more important of the two, because it determines the overall balance of Parliament. Parliament normally has 120 seats, although a party that wins more electorate seats than its party vote entitles it to can create extra ones, which is why the 2023 result produced 122 members.

A party generally needs at least five percent of the party vote, or one electorate seat, to enter Parliament. That rule is why small parties matter so much. The Greens, ACT, New Zealand First and Te Pāti Māori are all competing for support, and the Opportunity Party is considered a wildcard by analysts, according to the Konrad Adenauer Foundation. Seventeen parties are registered for this election, as reported by Scoop.

Because one party seldom wins a majority, governments are built through negotiation. Reuters explained that after the election the major parties can form a coalition or sign confidence and supply agreements with smaller parties. A coalition normally gives partners ministerial roles, while a confidence and supply deal usually means a party supports the government on key votes but remains outside the cabinet.

The 2023 election showed how it works. National won the most seats but needed both ACT and New Zealand First to reach a majority, and the talks took until late November. Many experts expect a similar process this time, with the leaders of smaller parties holding unusual leverage.

For voters, that means a ballot is both a choice of party and a choice of possible partners. Many people will think carefully about which combination they want to see in government, not only who becomes prime minister.