The Taoiseach told the Dail that the Irish and British governments had no alternative to the Belfast Agreement.
Mr Ahern was replying to the Labour leader, Mr Ruairi Quinn, who asked if the two governments had a plan B in the event of the Mitchell review process ending in an impasse or failure.
"We have not got a plan B," the Taoiseach said. "We are not contemplating a plan B. We have not discussed a plan B. I would rather not get into a plan B. I think we have an obligation to implement the people's agreement, which is the Good Friday agreement, negotiated in Belfast and concluded on April 10th last year, voted on by the people. There should not be another plan."
Asked by the Fine Gael spokesman on Northern Ireland, Mr Charles Flanagan, how long more the talks would continue, the Taoiseach said it had been said originally that they would conclude by the end of July. "Then it was the end of September. That is tomorrow. It will go on, I think, into a good part of October."
Mr Ahern said he wanted to assure the House that the Government was continuing to monitor the ceasefires of all paramilitary organisations in close consultation with the British government.
"I utterly condemn the murder of Charles Bennett and the activity of paramilitary organisations, particularly intimidation and punishment beatings, and the continuing sectarian attacks in Antrim and Down, and I welcome Mr Trimble's condemnation yesterday of loyalist violence.
"However, in the round, I concur with the Secretary of State's judgment that, although these matters are of the gravest concern, the IRA ceasefire has not broken down. On the question of what constitutes a breach of the ceasefire, the two governments are kept fully briefed on security matters by the security forces, North and South.
"But, in judging whether parties are adhering to the commitments they made, fine political judgments must be made looking at all the evidence in the round, and it is for the governments to make those judgments.
"Every effort must be made to ensure that the conditions are put in place that will copperfasten lasting peace and stability. There has been real progress in recent years, and we must not underestimate the benefits that the cease fires have brought. A political agreement is the only way to ensure that the tragedies of the past are not repeated."
On decommissioning, the Taoiseach said the only way it would ever happen, in the view of both governments, was under Gen John de Chastelain. "It will not happen any other way, and it is a hopeless exercise people believing it will happen any other way."
The Fine Gael leader, Mr John Bruton, commended the Taoiseach on his positive response to the Patten report on the RUC, and asked if he would consider implementing some of its recommendations in the Republic relating to the Garda. These would include training with regard to human rights and a form of local democratic involvement in the supervision of Garda activity in a general sort of way.
Mr Ahern said he would consider the suggestion.