Mr Blair said: "What we are trying to do, and will do with increasing urgency over the new few days, is to try and find a way of making sure that the whole of the [Good Friday] Agreement is implemented."

The prime minister's remarks come as the Good Friday deadline for the transfer of power to Northern Ireland approaches.

Both sides of the community in the province and the UK and Irish Governments will hold several meetings between now and next week in a bid to clear the way for the setting up of a power-sharing executive at Stormont.

Earlier Mr Blair defended the release of three IRA prisoners, freed despite a legal challenge by Home Secretary Jack Straw.

Tony Blair: Whole agreement must be implemented

Mr Blair denied that his own ministers were at war over prisoner releases, saying the whole Cabinet was fully behind the peace process

But Conservative Deputy Leader Peter Lilley is calling on the government to halt the early release of terrorist prisoners until "Sinn Fein-IRA have given in their arsenal of weapons".

IRA prisoners Thomas Quigley, Paul Kavanagh and Gerard McDonnell walked free from the Maze prison in Belfast on Tuesday night.

They were freed hours after a High Court judge in Belfast rejected an appeal by Mr Straw to halt their release for "judicial clarification".

Denis Murray in Belfast: "The judge found against the home secretary on every ground"

A fourth prisoner, Brighton bomber Patrick Magee - also subject to Mr Straw's appeal - will also be released this summer.

The Sentences Review Commission decided that Mr Magee - who is serving seven life sentences for the 1984 Brighton bombing which nearly killed then Prime Minister Margaret Thatcher - should be released on 22 June.

Meanwhile, Ulster Unionist leader David Trimble is coming under increasing pressure from loyalist parties opposed to the agreement to exclude Sinn Fein from the executive body.

Magee: Serving eight life sentences

Politicians from the Democratic Unionist Party, UK Unionist, Northern Ireland Unionist and United Unionist parties have called on the Ulster Unionists to support their bid to prevent republicans from holding ministerial office.

DUP deputy leader Peter Robinson said anti-agreement unionists had agreed at a strategy meeting at Stormont to draw up a petition forcing a debate on Sinn Fein's exclusion from the executive.

They had already attracted the support of one rebel Ulster Unionist member, Peter Weir, who attended the meeting.

Mr Robinson has said he will invite more Ulster Unionists "one by one if necessary" to sign the exclusion motion.

He said: "It was, after all, a commitment they gave to their electorate that they would exclude Sinn Fein from government if Sinn Fein was not exclusively committed to peaceful and democratic means."

To force a debate on Sinn Fein's exclusion, the anti-Agreement unionists would have to secure 30 names for their petition.

However, Ulster Unionist assembly member Michael McGimpsey accused the anti-Agreement camp of "opportunism".

Cross-community support is required for any motion before the assembly excluding Sinn Fein to succeed and republicans were accusing the anti-Agreement camp of "wasting time".

Sinn Fein national chairperson Mitchel McLaughlin said: "Obviously we can expect the rejectionist unionists to use all the procedural mechanisms available them to delay an executive with Sinn Fein but all they can do is delay the inevitable".