Judith Collins says James Shaw will lose his job before Simon Bridges does.
The bold claim comes amid speculation Bridges is set to be rolled by none other than Collins, and the Government's failure to come to an agreement on a capital gains tax (CGT).
"People need to always remember I've always been a very loyal member of the National Party caucus and the team, and I always support the leader of the National Party," Collins told The AM Show on Thursday morning, after two polls put her at or above Bridges as preferred Prime Minister.
Bridges is struggling, with only one in 20 voters saying they want him - while half the country backs the incumbent, Jacinda Ardern.
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But after New Zealand First spiked the push from the Greens and Labour to introduce a capital gains tax, Collins thinks Shaw's the one who should be watching his back.
"Let's put it this way," she told AM Show host Ryan Bridge. "The National Party leader is going to be there longer than the Green Party leader."
She hasn't spoken to Bridges since the spill rumours started earlier this week, saying she's been "busy with my work".
While repeatedly saying she is "absolutely pledging my support for the leader of the National Party", she declined to utter the words "through to the next election", despite prompting from Bridge (the host, not her present boss).
"This is simply a diversion… what you should be talking about is why the Green Party lost their green credentials. I am here to help them. They should come to the National Party because we care more about the environment."
Shaw laughed off the suggestion, saying they've achieved more of their goals in 18 months supporting the present Government than in the last 20 years, despite missing out on a CGT.
If Collins does become leader, she wouldn't rule out trying to lure NZ First back to National's side. Former leader John Key infamously ruled out working with NZ First in 2008 and 2011, but the poll numbers aren't quite as strong for National these days.
"People do vote for Winston Peters' party before an election thinking they're going to help National," said Collins. "I haven't seen it help National since the 1990s, but it is certainly an option people do take. So I think it's something that will no doubt be considered before the election."
Peters' early career was as a National MP, but he left the party in the 1990s to form NZ First. He backed National after the 1996 election, but since then has twice formed coalitions with Labour.
"My personal view is that whatever the party decides, I support," said Collins.