National says the decision to extend the parliamentary and local elections to four years needs to be decided by the public and not the Government of the day.
As part of the Labour and the Green's confidence agreement confirmed today - the Government also states it wants to work with political parties from across Parliament - including the Opposition - on issues that affect democracy including the length of the parliamentary term, the Electoral Commission's 2012 recommended changes to MMP and the electoral finance law.
But National's electoral law spokesman Dr Nick Smith said while National was open to extending it, he warned the electoral law should not be a "play thing" and the decision should be made by the public.
"National is open to extending the term to four years for parliamentary and local elections, but the decision must be one made by New Zealand voters by way of a referendum, not decided by MPs alone."
During the second leaders' debate in the run-up to the October election, Prime Minister Jacinda Ardern and National leader Judith Collins both said they supported a move from a three-year to four-year term.
New Zealand, along with Australia, currently have one of the shortest parliamentary terms in the world. The US has four years and the UK five.
"Any further changes like to the current 5 per cent threshold or one-seat rule should not be changed without a broad consensus. These rules were set with a 100 per cent consensus of the Parliament when MMP was established in 1995," Smith said.
Smith said Labour and the Greens needed to remember that any major changes to New Zealand's electoral law needed to have broad public support.
"The worry with this announcement is that the new Government is placing greater priority to its own interests and re-jigging the electoral laws for the next election than on the huge issues facing New Zealand in the wake of the Covid-19 pandemic.
However speaking about the agreement today, Ardern said she wanted cross-parliamentary consultation on constitutional issues, and such issues were usually put to the electorate in a referendum.
As part of the Labour and Greens' agreement, the Green Party agrees to support the Labour Government by not opposing votes on matters of confidence and supply for the full term of this Parliament but it can abstain from voting.