Former National Party leader Don Brash lobbied ACT MPs in Auckland on Wednesday as part of ongoing efforts to secure the party's leadership.
Dr Brash has made it clear he wants to roll Rodney Hide to save the party from what he describes as "political oblivion".
However, he is still a member of the National Party and has to get majority support from the five ACT MPs, which include deputy leader John Boscawen, party whip Hilary Calvert, Sir Roger Douglas and Heather Roy.
Mr Hide has written to party supporters on Wednesday, saying he will stay on as leader as long as he has the support of the caucus and the party.
Mr Boscawen and Ms Calvert have both said they would support Mr Hide in a leadership vote. With Mr Hide's vote, this would be enough to block Dr Brash.
Dr Brash says he met with Sir Roger and Ms Calvert on Wednesday afternoon to outline why he wants to be leader. He said the meeting was cordial and constructive, but would not reveal any other details.
He also would not comment on whether he would meet with Ms Roy, who has voiced her concerns about Mr Hide's leadership in the past, and said he had not met with Mr Boscawen.
Dr Brash told Checkpoint he hoped those MPs who are nervous or negative about him will wait for the results of market research he is having conducted.
"I'm taking a risk in that, because I don't know what the market research will say.
"If it says, in fact, that I can't do any better for ACT than Rodney Hide does, then I'll have egg on my face and I'll go back to pruning kiwifruit.
"But if the market research suggests that I can do significantly better, I'm hoping the ACT Party caucus will take that into account."
Hide surprised at Brash move
In a letter posted on his Facebook page, Rodney Hide says he was surprised when Dr Brash announced he would publicly contest the leadership.
Mr Hide said he has encouraged Dr Brash to join ACT since 2002, but more recently the pair held a series of meetings.
He said Dr Brash told him he would only join ACT as leader, with former Auckland mayor John Banks running in Mr Hide's electorate of Epsom - something Mr Hide could not agree to.
Mr Hide said that while he is confident of his colleagues' support, it is not something he has raised with them directly and it is a difficult matter to respond to as Dr Brash is not even a member of the ACT.
Prime Minister John Key said there is no reason why Mr Hide should not remain a minister if he lost the party's leadership.