Senator George Mitchell is expected to announce late next week that his review of the Belfast Agreement is over, after a final 10 days of talks aimed at breaking the impasse.
On his arrival in Budapest last night for a three-day visit to Hungary, Slovenia and Kosovo, the Taoiseach, Mr Ahern, said he did not think anyone should be "over-optimistic or over-pessimistic" about the situation. "We have a very hard, concentrated period ahead on this," he said.
Mr Ahern said no time limit had been imposed on Senator Mitchell, but he expected him to call an end to the review - which has now taken 9 weeks - at some stage.
Reliable sources believe Senator Mitchell will make that announcement by the end of next week.
Today Senator Mitchell will hold talks with the British prime minister, Mr Blair, in London before travelling to the US to brief President Clinton.
In a statement issued yesterday Senator Mitchell said that in addition to meeting the two prime ministers, he had also asked the Independent International Commission on Decommissioning for a report on its assessment of the situation.
He will return to Belfast on Sunday for informal talks with the parties. He will meet them formally on Monday and is expected to issue a detailed statement by the end of that week when the review is expected to be concluded.
Whether this statement will include his own proposals to resolve the impasse over weapons decommissioning and the formation of a multi-party executive in the North remains unclear.
Mr Ahern, who met Senator Mitchell in Dublin last night, said those involved in the review process "had been down this road before and we know that complex issues are still at stake".
A Government source last night said the Taoiseach's comments were aimed at "talking down any immediate talk of a resolution".
ail that he did not know if it would be possible for Senator Mitchell to resolve the impasse. He said ["]there are still a few weeks, at least, in that process and I do not want to contemplate what we will do at the other side of it." If that happens, we must pick it up very quickly".
After what has amounted to some nine weeks of discussions in Belfast with the seven pro-agreement parties, Senator Mitchell said he was convinced that they were ["]sincere and acting in good faith in seeking the full implementation of the Good Friday Agreement["].
However, while he said that all the pro-agreement parties ["]want devolution and decommissioning["], he gave no indication that either Ulster Unionists or Sinn Fein had moved from their own long held positions.
It is understood there are no plans for the Taoiseach to meet Mr Blair ahead of the publication of Senator Mitchell's report. The view in Government circles in Dublin is that neither Mr Ahern nor Mr Blair would favour getting involved with the parties in discussions at Stormont similar to those that failed to reach an agreement last July.
The Northern Secretary, Mr Peter Mandelson, said more time was needed to reach a lasting solution but he believed it could be done.
"There is neither a breakdown nor is there yet a breakthrough.
I am satisfied of the very serious way people are talking to each other. I am not putting a time limit on it. While we are making progress, while people are talking seriously, that process should continue."
He appealed for patience to be displayed towards the North's politicians. "They share the same goal. They are navigating a way through, and I believe that they will, but it requires more time for them to do so successfully," he said.
"I believe the issues involved are so serious, are so great, that they should be given any amount of time, any amount of effort. It has to be a robust conclusion."
Meanwhile, the UUP leader, Mr David Trimble, left for the US yesterday. He is expected to meet President Clinton's deputy national security adviser, Mr Jim Steinberg, in Washington on Friday. Mr Trimble will return on Sunday.
Mr Gerry Adams said decommissioning was a huge issue for unionists but insisted it must be a voluntary process and the necessary conditions had to be created, including the implementation of the agreement.
He said there was still a slim chance of a political breakthrough. "I am hopeful the small chance that there is can be nurtured. This is the best chance we have of resolving all these issues," he said.