Mr Hague was speaking in Blackpool at the Tory party conference.

Sinn Fein was invited to a fringe meeting at the conference, but the invitation was withdrawn last week.

William Hague said he was prepared to talk to Sinn Fein leader Gerry Adams and would listen to what he had to say.

But the Tory leader said he was concerned that loyalists and republicans were not living up to the commitments they made last year, when the Good Friday Agreement was signed.

Mr Blair said his criticism of Tony Blair's handling of the situation did not mean the Conservative party no longer supported the agreement.

Process 'under stress'

Mr Hague's comments came after Sinn Fein chief negotiator Martin McGuinness warned the Good Friday Agreement could collapse within weeks, unless progress was made in the current review being chaired by former US senator George Mitchell.

Mr Mitchell had earlier warned that the process was under "great stress".

The review chairman said it was no exaggeration to say there was a real threat of the peace process not proceeding.

The Mitchell review was sparked by the collapse of talks at Stormont in July, following the Ulster Unionists' refusal to sit in government with Sinn Fein until the IRA began to decommission its weapons.

Sinn Fein say that it is a pre-condition that is not in the Good Friday Agreement.

Jeffrey Donaldson: An alternative must be considered

But prominent anti-agreement Ulster Unionist Jeffrey Donaldson said if the Mitchell review failed, there should be an alternative means of providing local government.

Speaking on Tuesday night from the Conservative Party Conference, Mr Donaldson said a choice had to be made between political stalemate and political progress.

"The people who are holding up progress, that is those linked to terrorist organisations, who are continuing their violence and refusing to decommission their illegal weapons, should be set to the side," he said.