How Labour voters handed Green MP Chloe Swarbrick Auckland Central

Epsom is still the bastion of strategic voting, but as new election details show that people splitting their votes in Waiariki and Auckland Central were also key in delivering a win to a candidate from a small party.

The detailed election statistics show that overall 32 per cent of people split their votes in 2020 by supporting a candidate from a different party to their party vote.

That included 22 per cent of Labour voters (318,280 people) but just 12 per cent of National voters (91,651).

Epsom was again the electorate in which there was most vote-splitting - 56.5 per cent of voters split their vote in the Auckland electorate which has been held by an Act Party MP since 2005.

The difference between the vote splitting in 2017 and 2020 told the story of the wider election: in 2017, only 9 per cent of Labour voters gave their candidate vote to Act leader David Seymour.

In 2020, that rose to 23 per cent – most likely voters who had switched their support from National to Labour for 2020.

Epsom was the only electorate in which National won the party vote, but Labour's vote shot up from 9500 to 15,000 while National's had dropped from 22,900 to 15,700.

Act's party vote also rose from just 696 in 2017 to 4355 as disgruntled National voters found a new home.

Epsom has been the den of strategic voting since 2005, when then Act leader Rodney Hide first won the electorate.

Since then, National has given the nod to its voters to continue supporting the Act candidate to ensure it had a potential government partner.

In the past, there have been half-hearted attempts by other parties to mount a counter-splitting strategy: the Greens and Labour have sometimes told voters to support National's candidate to try to edge out Act.

Auckland Central:

The campaign in Auckland Central was marked by debate about whether Labour and the Greens should do an Epsom-style 'deal' to avoid splitting the vote on the left between them – something that had been an issue in the past, allowing National's Nikki Kaye to hold on to the seat.

Green Party supporters celebrate as Chloe Swarbrick wins the Auckland Central electorate in 2020. Photo / Getty Images

No deal happened, but Labour voters took it upon themselves to do it: just over one third of Labour's voters supported the Green's Chloe Swarbrick over Labour's Helen White.

Swarbrick's higher profile was likely another factor in the result in the seat.

Swarbrick's chances were also boosted by the controversy in National after Kaye stepped down just a few months out from the election, leaving new candidate Emma Mellow little time to rally.

Overall, 37.5 per cent of Auckland Central voters split their vote.

Waiariki:

It was Labour voters in Waiariki who handed the Maori Party its road back into Parliament.

The Maori Party ran a split vote campaign, urging voters in the Maori seats to give them the candidate vote only.

It worked particularly well in Waiariki – one third of Labour Party voters gave their candidate vote to the Maori Party's Rawiri Waititi instead of incumbent Labour MP Tamati Coffey.

Waititi's percentage of Labour votes was high compared to the other Maori seats.

Across the seven Maori seats, 22.5 per cent of Labour voters gave the Maori Party candidate a tick.

Maori Party co-leader Rawiri Waititi on his way to be sworn in as an MP. Photo / Mark Mitchell

Overall, 45 per cent of Waiariki voters split their vote and more than 8100 of Waititi's 12,390 votes came from split votes.

Coffey became the only incumbent Labour MP to lose a seat as a result.

The failed attempt: Northland

In Northland, National's Matt King was pipped at the post by Labour's Willow Jean Prime, who took the seat for Labour for the first time.

The third runner was NZ First's Shane Jones, who was put up by NZ First in a bid to win an electorate as a back-up plan.

Any hopes Jones had that Labour voters would split their vote to save Labour's coalition partner were dashed.

Only 11 per cent of Labour voters did that – and 14 per cent of NZ First's voters voted for Prime instead of Jones.

One third of voters split their votes in Northland overall.

There are several reasons for vote splitting other than for strategic reasons.

In electorates where an incumbent MP is considered safe, some voters either vote for the recognisable name or do not bother voting for a rival who is likely to be unsuccessful.

Those who party vote for a small party are more inclined to split their votes, even if their party of choice has a candidate. For example, almost 80 per cent of Act voters split their votes and 82 per cent of NZ First voters did.

In others cases, if a local MP is considered highly effective voters can be party-blind, and vote for the person regardless of the party they represent.

Almost 116,000 people who gave their party votes to Labour voted for a National Party candidate.

Had those voters all given their party votes to National as well, Labour would not have a majority and would have 60 seats, while National would have 38 seats instead of 33.

The statistics show 76,679 people voted for Green Party candidates but gave their party vote to Labour.

Had those voters also given their party vote to the Green Party, the Greens would now have 14 MPs and Labour 61.