Prime Minister Christopher Luxon has promised to hold a referendum on the MMP voting system if his government wins the 7 November election. He wants the vote to happen in 2027.

Luxon made the promise in an interview on Newstalk ZB on Thursday morning. He also pledged a separate referendum on extending the parliamentary term from three years to four. (RNZ)

The promises come about three months before election day. Voting places open from 9.00am to 7.00pm on Saturday 7 November. Preliminary results come out progressively from 7.00pm on election night. Official results are due on 27 November. Campaigning is not allowed on election day itself. (Elections NZ)

MMP stands for Mixed Member Proportional. It is the system New Zealand uses to elect its Parliament. Under MMP, each voter gets two votes: one for a local candidate and one for a political party. The number of seats a party gets in Parliament is based on its share of party votes. Because no single party usually wins enough seats to govern alone, parties form coalitions to reach a majority.

Luxon wants the MMP referendum held in 2027, the year after the November election. That would put any changes to the voting system into the first year of a second term, if the National-led government is returned.

Labour leader Chris Hipkins dismissed the MMP referendum as unnecessary. He pointed to a 2011 referendum where 58 percent of voters chose to keep MMP. He said that result showed clear public support for the current system. (RNZ)

Hipkins argued that any public dissatisfaction with MMP came from Luxon's leadership. He accused New Zealand First leader Winston Peters and ACT leader David Seymour of calling the shots without a public mandate.

The idea of a referendum on the parliamentary term has independent backing. The Independent Electoral Review's final report, released in January 2024, recommended holding one. (Beehive)

The broader context here is that putting the two referendums together carries political weight. An MMP vote re-opens a question voters last settled 15 years ago. The term-length change has failed at the ballot box before. Together, the two votes put the basic rules of New Zealand's democracy on the campaign agenda.

Running both votes in 2027 concentrates the risk into one year. If the government wins re-election, that approach builds momentum for both changes. But it also gives opponents a single target. The opposition can campaign against both referendums as a package.

Hipkins's approach signals the likely argument from Labour's side. By saying discontent with MMP is really about coalition dynamics, Labour can argue the problem is the government, not the voting rules. That frames the MMP referendum as a vote on Luxon's handling of the coalition rather than a neutral constitutional exercise.

How the public responds to that argument depends on whether voters can tell the difference between a government performing badly under MMP and the MMP system itself. The 2011 result suggests most voters were satisfied with MMP. For a referendum to produce a different outcome, that level of satisfaction would need to have shifted significantly.