After his shock demotion, Simon Bridges says National Party leader Judith Collins will go to any length to hold on to her leadership of the National Party.
Collins demoted Bridges to the back benches over a five-year-old complaint about lewd comments at a party function.
"What we saw yesterday was truly desperate stuff from Judith Collins," Bridges said in a short stand-up this morning.
"I think it shows that she'll go to any length to hold on to her leadership of the National Party.
"There's a huge amount I want to say about what happened yesterday and how wrong it was, and I assure you I will, but I want to talk to my caucus first and be very clear with them about what I think, and what I think should happen for the National Party."
Bridges said he asked for a caucus yesterday when Judith Collins was still in the precinct "but she wouldn't have a caucus yesterday, finally we have one this morning".
He said he would answer more questions after the 9am caucus today.
RNZ has been told Waitaki MP Jacqui Dean made the complaint in early 2017 and Bridges was spoken to, and then personally apologised.
Collins last night said she had only just learned how serious the complaint was and had no choice but to act.
The shock demotion, announced in a late evening media release, followed months of speculation that Mr Bridges may challenge for the leadership.
National MP Simon O'Connor said the party must get rid of Collins as leader.
He said he could not work with her and was handing over his portfolios.
"The way that this has been handled is just outright appalling" he told Morning Report.
O'Connor said said it was just dropped on caucus, and it was important they heard from both Simon Bridges and Jacqui Dean.
"This is just ongoing dirty politics.
"Judith's leadership is no longer sustainable."
National Party MP and Covid-19 response spokesperson Chris Bishop earlier told Morning Report Bridges did not to his knowledge try to call a caucus meeting yesterday.
"Judith enjoys the support of the caucus," he told Morning Report.
"Clearly we have an issue we need to ventilate and talk about which I'm sure will happen this morning.
"Pretty interesting evening last night with a press release coming out like that so clearly we're going to want to talk about that.
Bishop said no colleagues had asked him to challenge for the party's leadership, and asked if he would, he said he was just getting on with his job as Covid-19 response spokesperson.
"I've got than enough work on my plate"
Collins is expected speak to media at 10am along with Jacqui Dean.
In last night's media release Collins said her move had the unanimous support of the board of the National Party.
Bishop confirmed that under party rules a leader was not required to seek the board's approval to remove portfolios from a shadow minister.