The Taoiseach issued a strong warning against a return to republican paramilitary violence in the North. Mr Ahern said if some organisations were contemplating the use of violence for political ends, they should recall the actions and the determination following Omagh.

"I am frankly dismayed that there remains any organisation that claims to be republican that would be contemplating any further acts of violence in clear defiance of the wishes of all Irish people.

"While they invoke Wolfe Tone's end, complete separation, they have entirely forgotten and ignored his means, which was to unite Protestant, Catholic and Dissenter under the common name of Irishman. The Irish Government will act quite ruthlessly within the laws passed by the Oireachtas against any group which tries to restart the terrorist violence of the last 30 years."

On decommissioning, he said: "We believed, in concluding the Good Friday agreement, that we had found a way to provide the conditions and the formula whereby political progress and decommissioning would, and could, take place sooner rather than later. Eight months on from the signing of the agreement, it is disappointing that the issue could remain an obstacle.

"We must recognise that for all of us there are difficulties. That stalemate is the enemy of everyone. The progress we have made, we have made together, bringing our supporters and the people with us.

"At all stages of the peace process, it was agreed that a normal civil society was the ultimate goal, and on the nationalist and republican side that this would involve complete demilitarisation. An armed peace is not demilitarisation. If the agreement and its institutions are to work, then their establishment must be accompanied by a tangible commitment to dismantling on all sides the structures and arsenals of conflict."

Speaking during a debate on the North, Mr Ahern said he would have wished to be able to report to the House that the implementation of the Belfast Agreement was on schedule.

"After the overwhelming endorsement of the agreement, which so clearly now embodies the will of the people, North and South, I would have expected the executive to be meeting at least in shadow form, likewise the NorthSouth ministerial council and the British-Irish council to have held its inaugural meeting in shadow form."

The Fine Gael leader, Mr John Bruton, believed the paramilitary organisations would decommission within the two years provided for in the agreement. "I believe there are mixed sentiments within those organisations on the topic. I do not think it is decided that they will, but I believe it is inevitable that they have to."

The Labour leader, Mr Ruairi Quinn, believed the remaining obstacles to implementing the agreement could be overcome. "I say so because the momentum generated behind the peace process is too great. In effect, there can be no turning back."

The Democratic Left leader, Mr Proinsias De Rossa, said there was a need for nationalist members of the Northern Ireland Assembly in general, and Sinn Fein members in particular, to acknowledge the political difficulties faced by Mr David Trimble. "With the support of a bare 50 per cent of unionist members in the Assembly, Mr Trimble's room for manoeuvre is severely limited. Some realpolitik is required if the process is not to run into the sands once again."

Mr Caoimhghin O Caolain (Sinn Fein, Cavan-Monaghan) said he had to reflect the deepening disappointment - indeed the disillusionment - among growing sections of republican and nationalist opinion that over eight months after the conclusion of the agreement, its central elements had yet to be put in place.