Mixed-member proportional is the system New Zealand uses to elect our parliament – but how does it work?

With the 2023 election season in full swing, you’ve probably seen the term MMP being thrown around. If you’re new to the voting game, or even if you’re not, you might not be exactly sure what it means. Don’t worry, there are only a few ideas to get your head around, which are as follows:

What does MMP stand for?

MMP means “mixed-member proportional”. It is the system New Zealand uses to elect parliament, our highest-ranking group of politicians.

Voting under MMP

Under MMP, New Zealanders have two votes every election: the electorate vote and the party vote. 

The electorate vote is used to decide who your local representative will be. The candidate who receives the most votes in an electorate wins it for their party – for example, National leader Christopher Luxon is the member of parliament (MP) for Botany. 

The party vote signals which party you want to govern New Zealand at large – not just your local area. The party vote determines how many MPs parties can bring off their “party list”. 

Can I vote for different parties with my two votes?

It is 100% fine to vote for one party with your electorate vote and a completely different group with your party vote. 

What are electorates?

New Zealand is split into 72 regions – called electorates – for election voting. There are 65 general electorates and seven Māori electorates. All New Zealanders can vote in general electorates like Invercargill, Northland and Wellington Central, but you must have indigenous whakapapa to vote in Māori electorates such as Tāmaki Makaurau and Waikato-Hauraki. Tāngata whenua voters have to choose whether to vote in the Māori or general electorates – not both – three months before an election. 

The electorate you vote in is determined by where you registered your home address with the Electoral Commission. You can only vote in one electorate, even if you split time living between different areas. 

Some electorates are geographically enormous, like the Māori electorate Te Tai Tonga (covering much of the Wellington region and the whole South Island), and some are comparatively tiny, such as the general electorate of Mount Roskill (covering eight Auckland suburbs). 

What is a party list?

There are 120 MPs in parliament, and since there are 72 electorates, the 48 remaining positions are decided by how much of the party vote political groups get (minus the number of electorates they win). Political parties fill their party vote positions in parliament through a process known as the “party list”, which ranks their candidates. Party leaders like Chris Hipkins and Luxon occupy the number one spot on their respective party lists, followed by their deputies then high-ranking MPs and so on. 

The allocation of parliamentary seats 

Parties place electorate MPs in parliament first, followed by party list MPs. Overall, the combination of a party’s electorate and list MPs is roughly equivalent to the percentage of the party vote they received. However, not all parties make it into parliament, and the “wasted vote” from unsuccessful parties is cast aside.

How do parties reach parliament? 

The easiest way for a party to reach parliament is by winning an electorate. Candidates who win their electorate are rewarded with a guaranteed seat in parliament. However, parties can also enter parliament if they don’t win an electorate if they get at least 5% of the party vote. 

During the 2010s, Act received less than 5% of the vote but was returned to parliament because David Seymour won Epsom. Between 2002 and 2019, the Greens failed to claim a single electorate, but they made it to parliament by getting more than 5% of the party vote. If a party wins one electorate and gets less than 5% of the party vote but enough for more than one MP (usually about 0.8% per MP), they can have as many MPs as their party vote percentage allows for. In 2020, Te Pāti Māori only won a single electorate, but they got enough of the party vote – 1.2% – to bring in two MPs. 

What happens if a party wins more electorates than its party vote allows for?

When a party wins more electorates than their party vote percentage permits, the number of MPs can exceed 120. The extra seats are called “overhang seats”, and they ensure said party receives fair representation. However, other parties may also be awarded additional seats in compensation. 

The first overhang seat was in 2005 when the Māori Party won four electorates but only enough of the party vote (3.1%) for three seats. Parliament also had overhang seats in 2008, 2011 and 2014. 

How is a government formed in MMP?

To become the government of New Zealand, a group has to have a majority of the 120 MPs in parliament (61 or more seats). But the only time one party has reached that mark on their lonesome was Labour in 2020 when they won 65 MPs. That means that most of the time, Labour or National must get support from smaller parties – like Act, the Greens and Te Pāti Māori – to govern New Zealand. Support arrangements can take different forms, and for a more detailed explanation, look no further than our editor Madeleine Chapman’s 2017 article “Winston Peters is the hot girl on campus: a sexy guide to MMP relationships“.

That’s all pretty confusing. What’s the TLDR?

There are several main points to remember about how mixed-member proportional elections operate, the most important of which is that you have two votes. Your electorate vote elects your local representative and your party vote signals who you want to run the country at large. You don’t have to choose the same party with both votes. To make it to parliament, a political party must either win an electorate or receive more than 5% of the party vote. The party, or group of parties, with 61 or more of the parliament’s 120 seats, forms the government.