Labour deputy leader Jacinda Ardern says she'd happily give up on being deputy prime minister to get her party a coalition deal after the election.

With the Labour Party looking like it'll need a coalition partner to stand any chance of forming a government after September's general election, the deputy PM role could become a significant bargaining chip.

Asked whether she saw a future in the role, Ms Ardern told Three's The Nation she'd be happy just for Labour to be in a place to negotiate roles and would gladly give up the second spot.

"If we are the position where we are negotiating those positions, then that's where I want us to be.

"My relative position actually doesn't matter to me," she said.

Ms Ardern said she'd be pleased to be the minister for children instead.

"So if am not deputy prime minister but I'm a minister, that is fantastic. That means we've won."

As for who Labour would prefer to give the deputy role to if it came to a choice between the Green Party and New Zealand First, Ms Ardern wouldn't say.

But she said a vote for Winston Peters' party was a "wildcard" in terms of the election outcome, while Labour and the Greens had a memorandum of understanding to change the government.

While Ms Ardern has previously stated she isn't interested in being prime minister, a 1News Colmar Brunton poll earlier this month had her just ahead of Labour leader Andrew Little as the preferred person for the top job.