The Taoiseach has signalled his readiness to resume dialogue with Sinn Féin and rejected suggestions that the present republican leadership has failed.
In London yesterday Mr Ahern declined repeated invitations to say he accepted the "good faith" of the Sinn Féin leadership of Gerry Adams and Martin McGuinness.
But he said he did not think Mr Adams and Mr McGuinness "would have put so much into the [ peace] process . . . not to see it through". He was hopeful that republicans could and would take the final steps necessary to achieve the full implementation of the Belfast Agreement and an inclusive political settlement in Northern Ireland.
Mr Ahern spoke to reporters after officially opening RTÉ's new office and studio facilities at Westminster, following a 30-minute meeting with British Prime Minister Tony Blair at 10 Downing Street, having earlier addressed the annual Ireland Fund of Great Britain lunch.
He was asked if he agreed with commentators who had likened Mr Adams to Yasser Arafat, suggesting that the present republican leadership was discredited and that it was time for a new generation of leaders.
The Taoiseach replied: "No, I don't. I think Gerry Adams and Martin McGuinness have worked enormously hard at this project in trying to bring everyone with them."
While that might prove difficult, Mr Ahern continued, "I understand what they've been trying to do to bring everybody with them. And as far as Tony Blair and I are concerned we were always happy to work with the Sinn Féin leadership. At the same time we have to bring this thing to finality."
Mr Ahern said it was always inevitable that the process would get down to the small number of key issues concerning IRA links, decommissioning and criminality, and that following the murder of Robert McCartney in Belfast "it became clear to the public what the remaining issues were and what answers they want".
He said the only solution the nationalist and broader community wanted on that issue was to see everything done that would bring the murderers to justice.
Asked by The Irish Times if his answer to the Yasser Arafat question implied he accepted the good faith of the Sinn Féin leadership, Mr Ahern said: "I do not think Gerry Adams and Martin McGuinness would have put so much into this process - and they have for a long time, and they've risked a lot in this - not to see it through."
Pressed on whether Mr Adams and Mr McGuinness were acting in good faith, the Taoiseach said: "I think they're endeavouring to find a comprehensive solution, and I think they were.
"As I've said before, in those last few days before December 8th [ when the last political negotiations broke down] they went to the IRA and asked if a particular clause that we wanted could be inserted. And the word was No.
"Now I know what people said about that, that they went to themselves. I don't think it's as simple as that with Gerry Adams and Martin McGuinness. I don't want to be making this difficult in the week of their conference. But there are difficult issues to resolve."
Asked again if he accepted their good faith, Mr Ahern said: "I accept that they want to see a comprehensive deal. The difficulty for the Sinn Féin leadership is that there are people linked to them in the IRA who are involved in these activities."