Prime Minister Christopher Luxon has told Newstalk ZB there should "definitely" be a referendum on extending Parliament's term from three years to four, and he is open to also asking voters whether New Zealand should keep MMP.

MMP stands for Mixed Member Proportional. It is the voting system New Zealand has used since 1996. Under MMP, the number of seats a party gets in Parliament roughly matches the share of votes it receives nationwide. The last time voters were asked whether to keep MMP was 2011, when 57.8 percent chose to stick with it. RNZ

Luxon's comments caught his coalition partners off-guard and seemed to surprise his own National Party colleagues. Deputy leader Nicola Willis said she knew Luxon held those views and that they had been talked about in caucus and with the public. Justice Minister Paul Goldsmith said on Thursday it made sense to look at the four-year-term and MMP questions together. RNZ

Reuters reported that a referendum on New Zealand's electoral system could happen as early as 2027 if Luxon wins the general election scheduled for November 7, 2026. In the same interview, Luxon repeated his support for a four-year parliamentary term instead of the current three-year one. Reuters

The push for a four-year term is not new. A review of the electoral system released its final report in January 2024 and recommended a referendum on the length of the parliamentary term. The government agreed to introduce a bill for that in February 2025, and it passed its first reading — the first vote in Parliament — in March 2025. The government then set the work aside, saying it was short on time and wanted to focus on law and order policies. Beehive

University of Otago law professor Andrew Geddis warned against holding an MMP referendum at the same time as a four-year-term referendum. He said combining the two questions would confuse voters and weaken the legitimacy of the result. The electoral-system question should come first, he argued, before the question of how long Parliament sits. RNZ

Geddis also said it was unclear what the alternative to MMP would be, and called Luxon's openness to a combined referendum "a little bit of a brain explosion" after the problems of the previous couple of weeks. RNZ

The broader context here is that these big constitutional questions are being raised through radio interviews rather than through a proper policy process. Luxon's MMP comments came with no Cabinet paper, no published timeline, and no terms-of-reference document. The four-year-term bill already in Parliament had been parked by the government itself, so reviving referendum talk on both topics is a shift from the government's own plan.

Geddis's concern comes down to a simple point. If a voter is asked at the same time whether to keep MMP and whether to give Parliament a four-year term, those are two separate questions with different effects. A four-year term under MMP means one thing for how often governments face voters. A four-year term under a different system — like first-past-the-post, where the biggest party wins all the power — means something else entirely. Putting both questions on the same ballot makes it hard to know which decision drove the overall result.

It is a bit like being asked in a single vote whether to extend your gym membership and whether to switch gyms. The answer to one might depend on the other, but combining them on one form makes it hard to tell what people actually wanted.

For the coalition, the practical problem is keeping everyone on the same page. ACT and New Zealand First both have their own histories with electoral reform and with MMP. Luxon's comments on Newstalk ZB did not appear to have been checked with coalition partners before he went public. Willis saying the views had been discussed in caucus helps close that gap, but it does not answer whether ACT or NZ First were consulted first.

The 2026 election is three months away. A referendum in 2027 would need a law to be written, introduced, and passed by Parliament, and the Electoral Commission would need enough time to design and test the ballot questions. The government already set aside its four-year-term referendum legislation once because of time pressure. Whether it will revive that work and add an MMP question is not yet clear.

What is clear is that the Prime Minister has put both questions on the public agenda in an election year where they were not expected to feature, and the experts closest to the issue are urging caution about the approach he has signalled.