A caucus meeting where minister Heather Roy is expected to be dumped by her parliamentary colleagues as deputy leader of Act is under way in Wellington.

First-term Act MP John Boscawen is expected to take her jobs as deputy leader and a minister.

Former Act MP Stephen Franks has just arrived at the meeting.

He is a lawyer and it is thought he is there to give Mrs Roy advice.

Mr Franks refused to talk to reporters. He left Act and stood for National at the last election.

Mrs Roy is said to again have been trying to rally party opinion against Rodney Hide.

At the end of the last year, the Herald revealed that Mrs Roy and party founder and MP Sir Roger Douglas had led an unsuccessful move to oust Mr Hide as party leader.

A special caucus meeting was held, but no vote was put.

Today's caucus meeting is expected to be a fiery one. Mrs Roy is not expected to go without a fight, and she is likely to have Sir Roger on her side.

Mr Hide is almost certain to have briefed Mr Key on the latest internal turmoil, as he did last year before the leadership meeting.

Neither Mrs Roy nor Mr Hide would speak to the Herald last night.

Act has only five MPs - Mr Hide, Mrs Roy, Sir Roger, Mr Boscawen and David Garrett.

Prime Minister John Key said he would have a discussion with Act leader Rodney Hide following any decision made about the Act deputy leadership.

He did not want to speculate on who he could work with as a minister in the Act caucus until a decision was made.

When asked if he had confidence in Heather Roy as a Minister of the Crown, he said: "Right at the moment, yes."

He again ruled out working with Sir Roger Douglas as a minister, as he had done before the 2008 election.

"His agenda is a far right agenda and that doesn't sit well with a centre-right Government."

He said he "absolutely" had a say in who would replace Mrs Roy if she was ousted as deputy leader.

"And constitutionally it's my responsibility.

"If there was a change in deputy leadership then I would anticipate having a conversation with the Act leader [Rodney] Hide."