The Green Party has decided not to run a candidate in Ohariu to give Labour a better chance at unseating United Future leader Peter Dunne.
That is despite the Green Party previously expressing concerns about the Labour candidate Greg O'Connor's position on several issues.
Green co-leader James Shaw said his party's national executive decided against running a candidate in Ohariu "because it increases our chances of changing the Government".
Dunne won the seat by just 710 votes in 2014, while the Green Party candidate Tane Woodley received 2764 votes.
Woodley will campaign for the party vote in the electorate this year but will not put his name on the ballot paper.
The Greens have expressed concerns about O'Connor's comments in his previous role as Police Association president, where he was an advocate for arming police and taking a tougher stance on drugs.
Shaw said the party was now willing to put those differences aside.
"Greg has said things in the past that progressive voters would take issue with.
"I would suggest that people question him about those statements. They've got to decide for themselves whether they're satisfied with the answers to those questions.
"But my view is that the greater priority is to change the Government."
Labour and Greens last month said they had agreed not to cut "deals" in marginal seats as part of their Memorandum of Understanding.
Shaw said the Green's decision not to run in Ohariu was made by his party alone and was not part of a formal arrangement with Labour.
Dunne has held the seat since 1984 and his party has been a support partner for National since 2008.