The Electoral Commission will review MMP and make recommendations on how to make it better after voters chose to retain the system in a referendum held alongside last month's general election.
The referendum asked whether voters wanted to keep the proportional representation system introduced in 1996, or change to another system.
A second question asked which alternative system voters preferred from a list of four options.
The Electoral Commission released the finalised referendum results on Saturday, showing 57.8 per cent wanted to retain MMP, while 42.2 per cent wanted to change to another system.
The old first-past-the-post (FPP) system was the preferred alternative, with 46.7 per cent of the votes.
A further 24.1 per cent wanted a change to supplementary member (SM), which was the system promoted by anti-MMP lobby group Vote for Change, while 16.7 per cent chose single transferable vote (STV) and 12.5 per cent chose preferential voting (PV).
A review of MMP was planned regardless of the referendum outcome, and the Electoral Commission plans to announce a process and timetable for the review on Monday.
Keep MMP spokeswoman Sandra Grey says it's clear voters want MMP fine-tuned.
"We can now get on with updating our voting system without throwing the baby out with the bathwater."
Vote for Change spokesman Jordan Williams says the vote share for FPP shows there was an "undercooked debate" about the alternatives - in part because the National Party chose to keep out of it, while other parties and unions backed MMP.
"The trouble with the review is it's ultimately up to the politicians to pick and choose what, if any, recommendations they take.
"We think that any significant changes should be put to the people," he said.
Nearly a third of the 2,257,243 votes in the second question were disregarded, after 748,086 voters didn't clearly indicate the option they wanted to vote for.
A total of 62,469 votes in the first question were disregarded.
News home