Explainer | Is MMP the Best Electoral System for New Zealand?

Written by Kate Liebl

Prime Minister Christopher Luxon caught his caucus off guard with a promise to present a new referendum on the mixed-member proportional system (MMP) if reelected. Luxon’s proposition to “check in constitutionally” leaves many New Zealanders questioning whether MMP is the right electoral system for the country, and what other options may exist.

Mixed Member Proportional System

Mixed-member proportional (MMP) has been implemented in NZ since 1993, with its first general election in 1996. Under this system, eligible voters are able to utilise both a party vote and an electoral vote to have their say in parliament. The electoral vote dictates the candidates who are elected to parliament, while the party vote determines the number of seats each party gets in parliament. Remaining seats are filled with list candidates, chosen by internal party leadership.

MMP was originally implemented with 53.9% support in a 1993 public referendum (Electoral Commission, n.d.). With this system in place, elections have been proven to be more representative and diverse than prior systems. Over the past 33 years, parliament has become more representative of the population. Smaller political parties are far more represented, currently taking 35% of the popular party vote and 32.8% of seats in parliament (NZ Election Results, 2023). Before the change to MMP, minor parties only took four per cent of the seats in parliament despite gaining 30.28% of the popular vote (Parliamentary Service, as cited by New Zealand Parliament, 2021). Parliament has also become more diverse, with the percentage of women, Māori, and Asian/Pasifika people increasing since 1993 to the present day. In 2020, parliament was made up of around 50% women, 20% Māori, and 15% Asian/Pasifika (Electoral Commission, n.d.).

However, MMP is not without its flaws. There remains the problem of wasted vote syndrome: votes towards minor parties that do not meet the five per cent threshold or win an electorate seat do not count. Many will choose to vote for major parties that do not align as well with their views, or not vote at all. Dr Lara Greaves, political researcher studying wasted vote syndrome, emphasised, “people do generally like to back a winner” (Lee, 2020). 

Another major problem regarding MMP is that when these minor parties are elected, they often hold a disproportionate amount of power in the legislative body. Minor parties frequently play the role of kingmaker in parliament, a unique position that allows minor parties to dictate policy agenda. In the past, NZ First has filled this role, forcing the Labour and National parties to fight for their votes. The kingmaker position often leads majority parties towards changing their policy agendas to appeal to a minor party, so that they can achieve the votes needed to pass their legislation. 

In this upcoming election, the Opportunity Party could play a similar role. Opportunity's leader, Qiulae Wong, commented that the ability to work with either major party is “an important line to maintain and hold, because that’s what creates the stability and stops that pendulum from swinging so far” (Radio New Zealand, 2026). Minor parties also often gain seats in parliament by way of the coat-tailing rule, which allows parties that do not meet the five per cent threshold but win one or more electorate seats to fill seats proportional to their percentage of the vote with list MPs. The coat-tailing rule allows for some minor parties to gain more representation than others, or force parliament to change its size (Radio New Zealand, 2026).

Some critics also argue that MMP is functionally slower and less effective than previous systems. Overall, bills take longer to be passed under MMP due to increased deliberation within select committees and a greater variety of perspectives. However, fans of MMP would argue that this longer timeline could be seen as a positive, with increased scrutiny of government and of the specific wording of bills being passed into law. Additionally, some bills can still be passed within a few days under urgency.

What are the Alternatives?

After explaining the existing flaws of MMP, the question becomes whether there is a better system for NZ. While many electoral systems exist across the world, Luxon’s referendum, if reelected, will likely suggest similar alternatives to the ones proposed in a 2011 referendum of the same nature: First Past the Post, Preferential Voting, Single Transferable Vote, and Supplementary Member (Electoral Commission, 2011).

First Past the Post

First Past the Post (FPP) was the system used across NZ before the implementation of MMP in 1993. Under this system, people are given one vote for a specific candidate within their electorate. In the 2011 referendum on the subject, 46.7% of valid voters agreed that if NZ were to change their electoral system, it should be changed to FPP (Electoral Commission, 2011). 

While FPP is generally faster and more effective than MMP, it is far less proportional. Diversity across the legislature was more constrained across the use of FPP, with almost 96% of parliament being made up of major parties (Parliamentary Service, as cited by New Zealand Parliament, 2021). Parties also saw unequal representation in parliament compared to their popular votes. In the 1978 general election, the Social Credit party won 16% of the popular vote, but only 1 out of 92 (or one per cent) of the seats in parliament (Electoral Commission, n.d.). This problem is not unique to the Social Credit party, as many other minor parties have experienced the same phenomenon under FPP.

Preferential Voting

Preferential Voting, the system used by Australia, is a majoritarian system that requires a majority of over 50% for any candidate to be elected. On each ballot, voters will rank the candidates running. The least-voted candidates will continue to be eliminated, and their votes redistributed to the voter’s second choice until one candidate reaches a 50% majority (Motherwell, 2022). This system is generally regarded as fairer to candidates and eliminates wasted vote syndrome. In the 2011 referendum, 12.5% of valid votes hoped for a change to preferential voting (Electoral Commission, 2011).

One of the main concerns regarding preferential voting is the rise of informal voting and overall voter confusion. An informal vote is a ballot paper that is filled out incorrectly or otherwise cannot be counted towards the final vote totals. In the 2022 election, informal voting sat at above 5% in the House of Representatives and 3.4% in the Senate (Australian Electoral Commission, 2022). In contrast, New Zealand’s informal voting rate sat below 0.01% for the party vote and around 0.014% for the electorate candidates in the last general election (NZ Election Results, 2023).

Single Transferable Voting

Single transferable voting (STV) is very similar to preferential voting, under which voters rank candidates to be eliminated each round until a winner is determined. However, the threshold for winning an STV election is flexible, and the remaining votes can be transferred to a second-choice candidate to elect multiple positions when one reaches the quota. This system is used across many city councils and local electorates in the country (The Department of International Affairs, 2025). The switch to STV received 16.73% of the popular vote in the 2011 referendum on electoral systems (Electoral Commission, 2011).

Due to its many similarities with preferential voting, the positive and negative aspects are very well aligned: being strong in fairness and proportionality, but weak due to its complexity. 

Supplementary Member Voting

The supplementary member voting system was created as a median between FPP and MMP. Under this system, 75% of the seats in parliament would be granted to specific electorates, and the other 25% would be made up of list MPs taken by a second vote. This system received 24.14% of the valid votes in the 2011 referendum (Electoral Commission, 2011).

As a middle-ground electoral system, supplementary member voting retains some of the benefits of both MMP and FPP, but also some of the disadvantages. The system is less proportional than MMP, but holds more accountability within individual electorates. Jordan Williams, one of the advocates for supplementary member voting in 2011, commented, “you get your accountability in electorates - but you also… get that representation for minority groups” (Radio New Zealand, 2011).

Recommendation

With the opportunity for NZ to use any of these systems, or even create a new one, some may prefer a change to the electoral system. However, because each of these systems exhibits its own unique flaws, MMP is the best path forward for NZ. Especially with the possibility of implementing reforms to eliminate coattailing and to decrease the frequency of parties reaching kingmaker status, MMP has provided many improvements to elections across the last 33 years. Preserving MMP will allow for the most proportional and diverse parliament in the future, with the least confusion and maintain efficiency levels across the country.

References

Australian Electoral Commission. (2022). Informality (%) House of Representatives and Senate. Australian Electoral Commission. https://www.aec.gov.au/voting/informal_voting/summary.htm

Electoral Commission. (n.d.). What is MMP? Electoral Commission New Zealand. https://elections.nz/democracy-in-nz/what-is-new-zealands-system-of-government/what-is-mmp

Electoral Commission. (2011). Overall Results - 2011 Referendum on the Voting System. Electoral Commission New Zealand. https://electionresults.govt.nz/electionresults_2011/referendum.html

Motherwell, S. (2022). How does preferential voting work in Australia? Australian Broadcasting Corporation. https://www.abc.net.au/news/2022-04-21/how-to-preference-voting-australia-federal-election/100991154

Lee, I. (2020). Wasted vote syndrome and human behavior - Polling phenomenon to look out for as election nears. 1News. https://www.1news.co.nz/2020/07/04/wasted-vote-syndrome-and-human-behaviour-polling-phenomena-to-look-out-for-as-election-nears/

New Zealand Parliament. (2021). MMP turns 25 - looking back after quarter of a century. New Zealand Parliament. https://www3.parliament.nz/mi/get-involved/features/mmp-turns-25-looking-back-after-quarter-of-a-century/ 

NZ Election Results. (2023). Summary of Overall Results. NZ Election Results. https://www.electionresults.govt.nz/electionresults_2023/statistics/overall-results-summary.html

Radio New Zealand. (2026). Christopher Luxon wants a referendum on MMP - How does the current system work? RNZ. https://www.rnz.co.nz/news/politics/903857/christopher-luxon-wants-a-referendum-on-mmp-how-does-the-current-system-work 

Radio New Zealand. (2026). Opportunity’s Qiulae Wong makes a play for ‘kingmaker,’ aiming straight at NZ First. RNZ. https://www.rnz.co.nz/news/politics/597755/opportunity-s-qiulae-wong-makes-a-play-for-kingmaker-aiming-straight-at-nz-first 

Radio New Zealand. (2011). Supplementary Member system attracting support to replace MMP. RNZ. https://www.rnz.co.nz/news/politics/89414/supplementary-member-system-attracting-support-to-replace-mmp

The Department of International Affairs. (2025). Single Transferable Vote. The Department of International Affairs. https://www.stv.govt.nz/index.shtml