Former National Party leader Judith Collins has been forced to step down after her caucus issued a motion of no confidence in her this morning, interim leader Dr Shane Reti confirmed.

Reti has held a press conference after a backlash against Collins' sudden demotion of Simon Bridges saw her step down.

Watch the conference here:

Collins was voted out as National's leader after the party was locked in a caucus for more than three hours.

The former leader confirmed the news on her Twitter feed.

I am pleased to say that I am just the MP for Papakura again. It's been a privilege to take over the leadership of @NZNationalParty during the worst of times and to do so for 16 months. It has taken huge stamina and resolve, & has been particularly difficult because..

— Judith Collins (@JudithCollinsMP) November 24, 2021

Reti will be the interim leader of the National Party until a leader is chosen on Tuesday

Reti says the National caucus met this morning to discuss the press release put out by Collins last night.

Collins demoted Bridges to the back benches over a five-year-old complaint about lewd comments at a party function.

Bridges hit back this morning saying it was "truly desperate stuff" from Judith Collins who would go to any length to hold on to her leadership.

Reti says the caucus was concerned with the content of the press release and the process by which it was issued.

"The caucus moved a motion for a vote of no confidence in the leader and that motion was successful.

"As a result the honourable Judith Collins is no longer leader of the National Party."

Reti confirmed he will take over as interim leader until the caucus meets again next Tuesday to choose a new leader.

"On behalf of the caucus I'd like to thank the honourable Judith Collins for her valuable service to the party."

He says there was "always a sadness" in cases like this, but "we get up and lift our eyes to the horizon and get on with our work".

He says his job at the moment is to shepherd and guide the party through until the leadership decision is made.

Reti says he had not himself contemplated yet whether he would put himself forward for the position, as it was more important right now to shepherd the party forward.

"We're really looking for our new leadership team on Tuesday to bring us back to focus on the things that matter to New Zealanders. We are in the middle of a pandemic, we want to be bringing new thinking to the room, new thoughts, and that's going to be our focus under our new leadership team on Tuesday.

"Judith had an allegation that she needed to attend to, it was a serious allegation and so she took advice and made the best decision that she could last night."

He repeatedly said he does not reveal discussions in caucus, nor private conversations with his caucus colleagues.

National MP Jacqui Dean has issued a statement regarding the recent events. She says Bridges apologised at the time of the incident "about five years ago" but that his "inappropriate" remarks had continued to play on her mind.

She says Bridges has reiterated his apology in the past few hours.

RNZ.