The party's leader David Ervine said the governments were excluding him from the real negotiations.

The Northern Ireland Assembly has been suspended since 14 October following a row over allegations of IRA activity, including intelligence gathering at Stormont.

The PUP is closely linked to the outlawed loyalist paramilitary group, the Ulster Volunteer Force.

What we now want to hear from the prime minister is what he believes the republican movement must do to put the process back on its feet David Trimble UUP leader

Mr Ervine said his colleagues could not be expected to "rubberstamp" a deal they had no sight of during negotiations.

"It is clear there are things going on in the undergrowth - both political and paramilitary," he said.

"Unless we have a clear understanding, a clear sight of what those are it would be foolish for the PUP to take its place in the upcoming talks and be used simply for a pat on the head and to rubberstamp something we have not been party to.

"We are not prepared to play that game."

Earlier, Ulster Unionist leader David Trimble expressed doubts over whether elections to the Northern Ireland Assembly should take place in May.

Mr Trimble's comments followed a meeting with Prime Minister Tony Blair in Downing Street on Tuesday to discuss ways of restoring devolution to the province.

Mr Trimble said he wanted to see political differences over decommissioning resolved but he admitted that there was little time to secure a resolution before May.

Mr Trimble said time was running out for a decision on whether the institutions could be restored.

The hour-long meeting was the first in a series Tony Blair is holding this week with Northern Ireland parties.

Transition

SDLP leader Mark Durkan said unionists should "end their inconsistency and get down to the real business of moving out of the political crisis".

He pointed out that Mr Trimble had offered to hold talks with Sinn Fein after walking out of multi-party talks before Christmas.

Is this statement now DUP party policy or is Mr Hay running ahead of his leader Michael McGimpsey Ulster Unionist

"Now that he has clarified his resonance to meet Sinn Fein in a bilateral, there is no excuse for him not participating in the all-party talks," said Mr Durkan.

Mr Trimble walked out of the last meeting - with the British and Irish Governments at Stormont - over a leaked Irish Government position paper which said the IRA was still active.

In October, Mr Blair called for "acts of completion" from the republican movement to demonstrate that it has made the transition from violence to democracy.

He said this would enable the government to fully implement its part of the Good Friday Agreement.

Sinn Fein blame the difficulties in the process on unionists.

Blame game

"The unionists decided to pull down institutions which were driving the whole process forward," said assembly member Gerry Kelly.

Meanwhile, a senior member of the DUP said his party could "do business" with Sinn Fein but only if it became a normal constitutional party.

William Hay: His party could "do business" with Sinn Fein

Assembly member Willie Hay said that republicans would have to make clear their war was over and provide a timetable for IRA disbandment.

"We are saying clearly to the republican movement if you want to be involved," said the Foyle assembly member.

Ulster Unionist assembly member Michael McGimpsey called for clarification from the DUP leadership following the comments.

Later, DUP leader Ian Paisley played down the comments, adding: "The comments as reported to me do not reflect party policy and far too much is being read into their meaning anyway."

Following the collapse of power-sharing at Stormont, current legislation dictates that the British and Irish Governments must review the implementation of the Good Friday Agreement on which devolution was based.

But unless some common ground can be found between the parties on how to proceed, there is no mechanism for reinstating Northern Ireland's power-sharing executive.

Both the governments have stressed that there will be no re-negotiation of the Good Friday Agreement.