The North's First Minister, Mr David Trimble, has expressed his disappointment at the behaviour of some of his party's MLAs, who are expected to side with the DUP tomorrow in supporting an Assembly motion for the expulsion of Sinn Fein.
"It is unfortunate that people elected to the Assembly on a pro-agreement mandate at the first flicker from the DUP abandoned their manifesto commitments.
"I think that is a situation where people are not reflecting the obligation they entered into with the electorate," he told the BBC's Inside Politics programme.
So far, the Ulster Unionist MLAs, Ms Pauline Armitage and Mr Peter Weir, who lost the party whip last year, have signed up in support of the motion giving the DUP the 30 signatures necessary to table it. The DUP last night predicted that there would be "more seepage" from the UUP in support of Sinn Fein's expulsion.
The motion is expected to fail as it has almost no chance of securing the necessary cross-community vote from both nationalists and unionists.