The Assembly will sit in an extraordinary session tomorrow to debate an anti-agreement unionist motion calling for the exclusion of Sinn Féin ministers from government.
The motion, tabled by DUP members and two smaller unionist parties, comes three days before Saturday's annual general meeting of the Ulster Unionist Council, the ruling body of the UUP. Mr David Trimble, the UUP leader, said the move was intended purely to destabilise his party.
"If the people who put the motion in were serious, they wouldn't be sitting sharing power with Sinn Féin. They wouldn't sitting in committees with Sinn Fein. If they had integrity they would get out of here," he said.
The Speaker, Lord Alderdice, said anti-agreement unionists had called for the motion to be debated before March 9th.
The DUP maintained that recent events such as the alleged involvement of the IRA in the killing of Mr Matthew Burns in Co Down last month meant that Sinn Féin was no longer a suitable party for government.