Anti-agreement Ulster Unionist MP Mr Willie Ross has called for "urgent clarification in very large doses" of Mr David Trimble's comments in Washington that Sinn Fein could return to government without prior Provisional IRA decommissioning.
Mr Trimble faces an Ulster Unionist Council meeting on Saturday. Mr Ross said his leader must make clear if he was contemplating a "massive change in policy".
He said: "We seem now to be trying to move away from `guns before government' to a situation of `government without guns'. We would look absolute idiots if we let Sinn Fein/IRA in again without any guns being submitted."
Mr Ross said the UUP had previously "jumped first" but republicans hadn't followed. It was time Sinn Fein clearly proved it was prepared to live by democratic rules and ideals "rather than believing power always comes out of the barrel of a gun". "For the UUP to say in November `we are jumping first and expect others to follow', to then say in February, `Well, we jumped and they didn't follow and that is it', and then to come back at the end of March and say `We think they might jump this time, we are going to give them another go' is just not on.
"Anyone with any common sense knows it is not on. The party has a policy and the question is whether that policy is going to be adhered to by the leadership or whether they are going to try and change it again."
The UUP deputy leader, Mr John Taylor, and anti-agreement MP Mr Jeffrey Donaldson have both requested a meeting with Mr Trimble. Mr Donaldson said: "I do not understand why we should have to make another concession again. The onus is on republicans to deliver actual decommissioning. It would be an incredible decision if this party were to vote to go back into government with Martin McGuinness and Bairbre de Brun without a single bullet or explosive decommissioned."
There was also speculation that Mr Donaldson and Ms Arlene Foster, members of the UUP review group set up to advise Mr Trimble, were considering resigning from the group.
Mr Donaldson said its future would have to be considered following his meeting with Mr Trimble. Ms Foster said she was considering resigning but wanted to give her leader a chance to explain his comments.
The chairman of the Ulster Young Unionist Council, Mr Philip Weir, said there appeared to be little consistency on UUP policy. Party members hoped the new policy was not "getting back into government at all costs", he said.
The DUP deputy leader, Mr Peter Robinson, said it was time Mr Trimble "came clean" about his party's policy. "It is time David Trimble came clean about his intentions rather than continuing to tell friends in Washington one thing and his party another.
"It is a game he can only play for so long and which will ultimately catch him out. There appears to be no price David Trimble is not willing to pay to save his own job."
The Rev Willie McCrea of the DUP said the UUP must depose Mr Trimble "before he destroys every vestige of unionism within the party".