Jacinda Ardern sets sights on 2020, angles for deal with NZ First in Wairarapa

The Prime Minister is starting the election battle two years early - and she has the National-held electorate of Wairarapa in her sights.

A reasonably popular New Zealand First MP is standing in the way, and Labour looks to be angling for an Epsom-style deal.

After Simon Bridges' embarrassing expenses leak, Jacinda Ardern has gone as far as ordering her MPs to pile into vans for their regional road trips to keep costs down.

On Thursday, the ministerial carpool hit the Wairarapa, which Labour is setting up as a battleground seat.

An office was opened for MP Kieran McAnulty - ribbons were cut and babies cooed over. It was all the signs of the start of a campaign, two years out from an election.

"We're constantly making a play for seats that we've held before," Ms Ardern says.

National's Alastair Scott won the seat last year with a majority of nearly 3000, with the remaining votes split between Labour's Mr McAnulty and New Zealand First's Ron Mark.

If the parties did a deal, their combined votes would beat Mr Scott by nearly 5000.

A deal with New Zealand First wouldn't be unprecedented - Labour stepped aside at the last minute to make it easier for Winston Peters to win the 2015 Northland byelection.

The problem is Mr Mark is convinced Wairarapa belongs to him and his party.

"Deals are not in my DNA," he told Newshub. "We don't do deals. I will stand in the Wairarapa as I have done in the past."

Mr McAnulty says Labour will play the cards as they're dealt, but says if Mr Mark didn't stand, it wouldn't be because of a deal - it would be to focus on his portfolio.

Heading into an election with their colours nailed to the mast goes against everything New Zealand First has ever done. Aligning themselves with Labour could seriously compromise their negotiating position post-election - and it might even knock the kingmaker crown from Mr Peters' head.