National deputy leader Nikki Kaye has dismissed speculation of another leadership challenge before September's election as "ridiculous".
And she told Newshub Nation this morning she had a "moral obligation" to help roll Simon Bridges because the country was facing a Covid crisis and she didn't think he could win.
"This isn't tiddlywinks. We're fighting for our future and we had to make a decision, which was - are we going to be able to get a National Government, which the country needs?"
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She rejected the idea she and new party leader Todd Muller had been plotting a challenge for a year or several months.
"That is not correct at all. We were looking at the polls and that was not a year, it was not even months.
"We literally were waiting to see what that polling information showed. We had a moral obligation to do something because New Zealand needs a National Government."
She dismissed speculation there might be another leadership challenge before the election if the polls continued to show support for the party hovering around 30 per cent.
Muller would lift National's support back into the 40s, she said.
"To win the election, we're going to have to.
"We're not going to be standing down. We are certainly going to be lifting the polls."
Kaye highlighted the differences in opinion from PM Jacinda Ardern and Deputy PM Winston Peters about when to move the country to alert level 1, and the lack of clarity over a transtasman timetable.
Ardern has not put a timeline on transtasman flights, but has said September is a "reasonable" expectation.
Peters has said New Zealand and some Australia states, including Tasmania, have contained Covid-19 well enough to start flights now. He has not commented on speculation about July flights, saying it is up to Australia to decide when it will be ready.
A draft blueprint for transtasman flights - including how to screen each passenger without the need for quarantine on arrival - has already been presented to the New Zealand and Australian governments.
Peters has publicly agitated for a move to alert level 1, and is expected to continue to be vocal in his differences of opinion with Labour in the lead-up to September's election.
National's policy is not to work with Peters after the election to build a potential coalition, but Muller has left the door ajar for that policy to be overturned.
The latest UMR poll, leaked to the Herald on Friday, did not see any substantial boost to National following the leadership change.
Taken the week after Muller took over as leader, the poll had Labour on 54 per cent, National on 30 per cent - 1 percentage point higher than its previous poll - NZ First on 5 per cent and the Greens on 4 per cent.
She also admitted to her error in claiming frontbench MP Paul Goldsmith was Ngāti Porou.
She wouldn't say if she had misconstrued a text message from National MP Jo Hayes, who is Māori.
"I was advised by someone reasonably reliable in the building. I'm not going to go into who that was, but I made a mistake," Kaye said.
National has been criticised as having no ethnic diversity in its first 12 spots.
Kaye said the caucus was diverse, but there were only so many frontbench spots.
"The reality is there's only a certain number of spots. We accept as a leadership team that we have to own that representation issue."