Labour and the Green Party have been taking their electoral tandem out for a test ride around the Mt Albert electorate in recent weeks.
The campaigns of Labour's Jacinda Ardern and the Green's Julie Anne Genter are being pitched as a demonstration of how the two parties will work together in this year's General election.
Mt Albert by-election candidates Julie Anne Genter (Greens) and Jacinda Ardern (Labour) Photo: Green Party / RNZ
Ms Ardern is the favourite to replace David Shearer, who resigned at the end of last year to work for the United Nations in South Sudan.
Even though National is not standing a candidate in the safe Labour seat, the Green Party is - Ms Genter.
Last year, Labour and the Greens signed a memorandum of understanding that means they will work together to change the government at the general election.
That agreement has not extended to the Greens giving Ms Ardern a clear run at Mt Albert - a safe Labour seat.
Ms Genter said, in this context, by-elections do not have to just be about winning and losing.
"We are different, distinct parties with different policies on offer. Voters will have the opportunity to choose whether they want to be a bit more Green or a bit more Labour, but fundamentally we're demonstrating that we can work together and that politics doesn't have to be a battle or a game where you're just in it to win and defeat your enemy," she said.
The Greens decided to stand in Mt Albert because National was not.
"With National leaving their Mt Albert voters, completely, suddenly it's an opportunity for Labour and the Greens to be speaking to all of the voters in Mt Albert and making the case why we are the parties that should be in government after September," Ms Genter said.
Ms Ardern said she and Ms Genter were demonstrating there is a different way of doing politics.
"We have conversations about how the by-election is going for each other, just at a one-on-one level, but we're still running our own campaigns.
"For us, you'll see a campaign that hasn't been about attacking one another's ideas and policies, but just presenting our different vision to voters. And I think there's been an appreciation about a different style of politics."
Ms Ardern said there was nothing new about Labour and the Greens standing in the same seats - the memorandum of understanding has just pushed it into the spotlight.
"This is really just a stark example of an MMP environment. We will have parties that are saying, given the opportunity we'll be in coalition together, but we are still separately campaigning for party vote. That's MMP and it's not new, but perhaps it's, post the MOU, just become a little more obvious," she said.
Advance voting is under way, ahead of the by-election on Saturday.