Simon Bridges is confident his leadership is secure despite polls suggesting otherwise, and he's revealed his plan to probe Jacinda Ardern on the Budget leak scandal.
Bridges, the National Party leader, said he'll question the Prime Minister in Parliament about how much the Beehive knew about the leaked Budget material before Treasury issued a statement saying it had been hacked.
"They've failed the integrity test, so tomorrow you can expect me in Parliament to really strongly and forensically hold Jacinda Ardern to account on this," Bridges told Magic Mornings with Peter Williams on Monday.
Bridges told Magic Talk the ordeal was "fundamentally important and we will hold the Government to account on those things".
"[Ardern]'s going to be like a neutral umpire waiting for a decision. She's not the umpire, she's the captain of the team.
She should know what's going on in her team.
"She may well be involved in what's going on."
But last night's Newshub-Reid Research Poll found more than half the country thought National releasing the Treasury Budget details was the wrong thing to do.
Bridges said he understood there would be people who felt National should be going after the Government on important issues such as the economy or health.
"I get that - those issues are fundamentally important and we will hold the Government to account on those things," he told Magic Talk.
"But although this one may not have the same sort of everyday appeal to Mrs Jones in Tauranga, or Mr Smith in south Auckland, the reality is it's incredibly important because you see from a government its strengths and weaknesses around issues like this."
The Newshub-Reid Research Poll also found that Bridges' popularity had sunk to 4.2 percent as preferred Prime Minister, behind National MP Judith Collins on 7.1 percent, and well-behind Jacinda Ardern on 49 percent.
Bridges said the poll didn't concern him. He pointed to another Colmar Brunton poll released last night that put National ahead of Labour.
"The true story here, if I'm right on the polls and which one's accurate, there was no Budget-bounce, and in fact National was overtaking the Labour Party in this poll halfway through a term," Bridges said.
What my Caucus knows is that we're strong under me.
"That I have the backing of the Caucus, and so there will not be a challenge."
But both polls put Bridges behind Collins as preferred Prime Minister. He defended his position, telling Magic Talk: "There are always people who have leadership aspirations."
You can listen to the full interview above.
Magic Mornings with Peter Williams is live weekdays from 9am to midday.