National leader Todd Muller has resigned as leader of the Opposition and National Party.
In a statement today, he says the decision is "effective immediately".
"It has become clear to me that I am not the best person to be leader of the Opposition and leader of the New Zealand National Party at this critical time for New Zealand," he says.
"The role has taken a heavy toll on me personally, and on my family, and this has become untenable from a health perspective."
He says he plans to spend some time out of the spotlight with his family to "restore my energy before reconnecting with my community".
"I look forward to continuing to serve as a loyal member of the National Party team and Member of Parliament for Bay of Plenty."
SHORT NOTICE FOR NATIONAL
At the same time as the statement was released to media, National's caucus members were on an emergency teleconference call where they learned the news.
1 NEWS understands Mr Muller wasn't on the call, but a statement was instead read by his deputy leader, Nikki Kaye.
Ms Kaye has been confirmed as the acting leader after his resignation, and the party caucus will meet in Wellington this evening to "discuss the way forward", senior whip Barbara Kruiger confirmed today.
"Our thoughts are very much with Todd and his family at this difficult time as is our compassion and love for Todd."
Ms Kruiger says the resignation was a "shock" and that the new leader will be decided in the next 48 hours.
She refused to speculate on who make take the top job.
A CHALLENGING WEEK
Mr Muller's resignation comes after the party was rocked by scandal over the last week.
National MP Hamish Walker announced he wouldn't stand for re-election after leaking private information of Covid-19 patients, while health spokesperson Michael Woodhouse later admitted he too received the confidential information - although he says he didn't leak it.
Mr Muller initially suggested Mr Woodhouse hadn't received the information, before backtracking just one day later and admitting he knew he had.
Mr Muller has only been the National Party leader role since May 22, when he rolled then-leader Simon Bridges in a coup.
At the time, he told MPs he deserved to take over the leadership as the party wouldn't be able to win with Mr Bridges in charge.
Ms Kaye was chosen as the deputy leader after the coup, ousting Paula Bennett who later announced she's going to retire from Parliament rather than stand again.
Today's announcement comes after three other National MPs resigned in as many weeks, with Ms Bennett, Mr Walker and list MP Jian Yang all announcing their intentions to leave.
In his statement today, Mr Muller says he intends to stay as the MP for Bay of Plenty.
REACTIONS FROM GOVERNMENT LEADERS
Upon hearing the news today, Prime Minister Jacinda Ardern expressed sympathy for her political opponent.
"No matter what side of Parliament you’re sitting, politics is a difficult place," she said. "I have passed on my best wishes to Mr Muller and his family."
Deputy Prime Minister and NZ First leader Winston Peters says Mr Muller will "bounce back", calling him a "good man" and "unlike most of his colleagues he does have commercial experience".
"Leading a divided and incompetent caucus would have tested even the best leader. The National caucus now has the unenviable job of selecting its fourth leader since the Coalition Government took office."
MPS OFFER SUPPORT TO DEPARTING LEADER
Ahead of the leadership vote tonight, National's MPs are publicly sharing their support for Mr Muller.
Former leader Simon Bridges, who was rolled by Mr Muller less than two months ago, says he's thinking about the departing leader's family at this time and called the role "the toughest job in politics".
He wouldn't comment when asked whether he wants his old job back, saying: "Let's see what happens."
Fellow MP Mark Mitchell, who also competed for the leadership role in the coup, also shared his well wishes for Mr Muller and refused to comment on speculation.
A CHANCE FOR MINOR PARTY SUCCESS?
Even before Mr Muller's resignation today, the National Party's popularity has slumped as Labour soars in a recent polls.
Geoff Simmons, leader of the minor The Opportunity Party (TOP), says this is an opportunity for smaller parties like his.
"With the National Party imploding, the duopoly of the two largest political parties has been broken," he says.
"This year the minor parties will be providing the major opposition to an ascendant Labour Party."
Parties require a minimum of five per cent of the vote, or to win an electorate seat, to enter Parliament.