National MPs have gathered in Parliament for an urgent caucus meeting. 

It follows Judith Collins' late night move against Simon Bridges. 

There's speculation he'd been preparing to roll Collins as leader of the party. 

It is understood Bridges and the National MPs who back him, tried to call a caucus meeting last night but Collins blocked it. 

The National Party leader has relieved the former leader of his portfolios after being made aware of a serious complaint from a female caucus colleague. 

Newstalk ZB understands it was made by Waitaki MP Jacqui Dean, and relates to a comment Bridges made in her presence about five years ago, that was not directed at her. 

Collins says she's confident she will remain leader and the allegations can't be dealt with by sweeping them under the carpet. 

Bridges says Collins is acting out of desperate, and he'll have more to say later today 

MP Mark Mitchell, says her actions were "deeply disrespectful", while another MP, Bridge's brother-in-law Simon O'Connor, says Collins must resign. 

O'Connor has handed in his portfolios and told Mike Hosking he rates Judith Collins but some of her recent actions haven't sat well with him.

"I suddenly feel the need to resign my portfolios and call for her to resign the leadership immediately."

He said he hoped a number of other National MP's will see what's right and what's right for the party.

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