National MP Todd Muller has confirmed he will challenge for the party leadership on Friday and has told colleagues they can't win September's election under Simon Bridges.
The two-term MP informed Bridges and National Party president Peter Goodfellow of his challenge this afternoon.
Muller sent a letter to all National MPs, advising them of his decision to challenge for the leadership.
"It is essential that National wins this election," Muller wrote.
"I share the view of the majority of my colleagues that this is not possible under the current leadership."
Muller said the country faced the most enormous challenge since the end of World War II.
"Labour has failed to deliver on every measure it has set for itself in Government. This will not change and the consequences of it being re-elected at this time will be catastrophic for two generations," he wrote.
"Our communities and our economy are at stake. It is essential National wins this election."
Yesterday, Muller said "no" when asked about leadership ambitions by The Country on Tuesday, saying Bridges was "doing a bloody tough job well" and that nobody could predict now that National could not win the election.
"I do not believe we can sit here now, 130 days out from an election when we are about to tip into the greatest recession of a generation, that you can make that view that National cannot win.
"I don't believe it, I know the National Party caucus don't believe it, and I know Simon doesn't believe it."
Bridges said this morning that he was being challenged for the leadership after the Herald reported yesterday that a no-confidence vote would be mounted against him at the party's next regular caucus meeting on Tuesday.
The caucus will now meet on Friday as Bridges seeks to front-foot a challenge.
Calling the caucus meeting for Friday, rather than the usual weekly Tuesday meeting, means Bridges reduces the time his challengers have to lobby MPs for change.
Former Prime Minister Jim Bolger publicly voiced support for Muller on RNZ yesterday, saying National would be doing a lot of "soul searching" and he believed Muller had the skills to take New Zealand forward from Covid-19.
"Todd worked in my office when I was Prime Minister, worked with me as a councillor on the university council at Waikato. He's a businessman of significant experience working with the biggest company - Fonterra - working with Zespri the kiwifruit exporter and so on.
"He has a different range of skills, but they're going to be the totally relevant skills going forward."
Full text of Muller's email to National caucus:
Earlier this afternoon, I notified Simon and our Party President Peter Goodfellow that I would be seeking a ballot for the leadership of the New Zealand National Party as soon as is convenient for the caucus.
This country faces the most enormous challenge since the end of the Second World War. Labour has failed to deliver on every measure it has set for itself in Government. This will not change and the consequences of it being re-elected at this time will be catastrophic for two generations.
Our communities and our economy are at stake. It is essential National wins this election.
I share the view of a majority of colleagues that this is not possible under the current leadership.
I believe I am best placed to earn the trust of New Zealanders by September 19.
I will be talking to each one of you about how we can all pull together and be deserving of New Zealanders' trust.
I love this party and what we can do for our country.