Prime Minister Christopher Luxon has promised a referendum on the MMP electoral system if National is re-elected in the November election, alongside a separate referendum on extending the parliamentary term from three years to four.

Luxon told Newstalk ZB on Thursday morning that an MMP referendum is "something we should consider" and that he wants to see it happen next year. He also urged voters to back National on November 7 to avoid coalitions with parties that don't share his values or policies.

NZ First leader Winston Peters condemned the MMP referendum call as "inexplicable" and a "power grab," posting on Facebook that the move from first-past-the-post to MMP broke the "stranglehold" of two parties. He said the two old parties now want to change the electoral system to shore up their falling support.

Labour leader Chris Hipkins rejected the need for a referendum, pointing out that the 2011 referendum on the matter showed clear support for MMP, with 58 percent voting in favour.

The backdrop is a long history of electoral reform in Aotearoa. New Zealand adopted MMP — a proportional system where the number of seats a party gets in Parliament roughly matches its share of the vote — after a two-part referendum in 1992 and a binding vote in 1993, when MMP received 54 percent support. More than eighty percent of voters in 1993 wanted to change the system. MMP had been proposed by a Royal Commission, a government-appointed panel that reviews major policy questions.

Luxon's own stance on MMP has shifted. At a post-cabinet press conference on 9 September 2024, he said New Zealand operates within an MMP environment, that it was the system voters chose, and that a compromise was made. The Independent Electoral Review's final report, released in January 2024, had ruled out recommendations such as lowering the voting age to 16 and allowing all prisoners to vote and stand for election.

The broader context here is a governing relationship between National and NZ First that has been strained for months. Peters said in April that Luxon calling a confidence vote in his leadership "promotes doubt" and could invite further challenges. Peters has also declared NZ First poised for a "massive victory" at the 2026 election, while criticising Labour, National and the Greens. NZ First has separately introduced a Member's Bill — a bill introduced by an individual MP rather than the government — that would ensure a binding referendum on the Māori seats.

Luxon's pitch to voters frames both referendums as part of an argument for single-party government: vote National on November 7 to avoid coalition partners who don't share his values. If delivered, the two referendums would put the electoral system and the length of the parliamentary term before voters in the same cycle, reopening constitutional questions settled at the ballot box in 1993 and 2011. Whether that appeal lands with an electorate that has twice endorsed MMP, and whether the promise survives coalition negotiations after November 7, are the political questions now in play.