Bill English won't be giving Shane Jones a free run in Whangarei to secure New Zealand First's support in any post-election coalition deals.
NZ First leader Winston Peters upset the polls to win neighbouring Northland from National in a 2015 by-election.
But ex-Labour MP Mr Jones faces an uphill battle in Whangarei, with National's Shane Reti commanding a 13,000-strong majority at the 2014 election. The Prime Minister says it's "a bit of a headstart".
"But the locals won't be quite so focused on the personalities - they'll just want an MP who's going to work hard," Mr English told The AM Show on Monday,
"By his own admission [Mr Jones] has his own style. That'll get tested on the streets of Whangarei."
Mr Jones says he hasn't heard from either Mr English or Labour leader Andrew Little - but a few (possibly former) Labour MPs have been in touch.
"A couple of the former glorious members of the golden oldie rugby team have been in contact with me, but I haven't heard from the women's committee."
Mr Jones caused controversy in his time with Labour, saying the party had too many women - in his own words, "geldings" - and using his taxpayer-funded credit card to rent porn movies.
"I stood for the leadership of Labour. I accept that to the Labour voters, David Cunliffe was a more accurate reflection of who they are and where they wanted to go. The sooner I left that house, the better."
Mr Jones says he'll be working hard to win women back this time around - saying his controversial, maverick style will work better than Donald Trump's.
"Part of what Trump does, it resonates with a variety of voters. He's alienated most women - that's not my job in Whangarei."
Red, green… and black?
Labour and the Greens come as a package, but recent polling suggests they'll need NZ First onside to form a government.
Mr Jones also never got along with Labour's friends to the left. But now that former Greens co-leader Russel Norman is gone, Mr Jones seems more open to the idea.
"The Aussie bloke Norman, he's now swimming around in the ocean, answering to a magistrate for that, and that's where he belongs."
Neither Mr Jones nor party leader Winston Peters will say if they'd prefer to go into coalition with Labour or National. Mr English says there will be no negotiating until after the election.
"If you want to get on with me in a ka pai way, I'm gonna be a good guy to work with," said Mr Jones.
"But if people get personal and venal with me, then I enjoy the bodyslam myself."