Key facts
- New Zealand's electoral system is mixed-member proportional (MMP).
- MMP requires voters to cast two votes: one for a local candidate and one for a party.
- Party vote share determines a party's overall representation in parliament.
- Parties must achieve 5% of the party vote or win an electorate seat to gain parliamentary representation.
- Coalition governments have been the norm since MMP's introduction three decades ago.
- Minor parties often play a 'kingmaker' role in forming majority governments.
New Zealand's upcoming Nov. 7 election is expected to result in a coalition government due to the country's mixed-member proportional (MMP) electoral system. Polls indicate a close contest between the left and right blocs, meaning no single party is likely to secure a majority on its own.
The MMP system, adopted three decades ago, replaced the British first-past-the-post method. It was introduced to ensure smaller parties received better representation. Since its inception, MMP has consistently led to coalition governments, with the exception of the 2020 election where the Labour government won outright.
Under MMP, voters cast two ballots: one for their local electorate candidate and another for a political party. The party vote determines the overall proportion of seats each party will hold in parliament. While electorate winners become Members of Parliament (MPs) automatically, the remaining seats are filled from party lists to reflect the national party vote. Parties must secure at least 5% of the party vote or win at least one electorate seat to be represented in parliament.
Forming a government typically requires a majority of at least 61 seats in the 120-seat parliament. The MMP system often elevates minor parties to 'kingmaker' status, enabling them to influence coalition formation. Historically, New Zealand First has played this role, supporting both National and Labour governments. Te Pati Maori has also been instrumental in forming National-led governments. In the current political climate, the centrist Opportunity Party could also emerge as a pivotal force if it meets the electoral threshold.
The 2017 election exemplified the system's dynamics, where the National party won more seats than Labour but could not form a government. Labour subsequently formed a coalition with New Zealand First and a confidence-and-supply agreement with the Green Party.
A quirk of the MMP system is the potential for 'overhang' seats, where a party wins more electorate seats than its party vote share would normally entitle it to. This occurred after the 2023 election when Te Pati Maori won six electorate seats with only 3.1% of the party vote, leading to an expansion of parliament's size. Projections suggest this could happen again.