The Taoiseach, Mr Ahern, has called on the parties in Northern Ireland "to join with us in trying to make progress" when he and Mr Blair travel to Stormont early next week to inject momentum into the deadlocked talks.
As the efforts to form the Northern executive enter their final and most intensive week Mr Ahern declared yesterday: "What has to be done is quite clear but not very easy."
He indicated that he and Mr Blair had identified other issues where movement could be used to get goodwill to help resolve the decommissioning impasse.
He told a press conference in Berlin yesterday that, while there had been no movement on the key decommissioning issue for a long time, there had been progress on other issues such as the North-South bodies, human rights and the equality agenda.
"Both of us feel that the peace process needs a boost. Both of us feel that there are matters that have to be moved on, that there are understandings that have to be reached and tasks that have to be overcome, and I think it is likely that we will end up there on Monday or Tuesday," he said.
The exact timing of their arrival depended on their dealing with parliamentary commitments Mr Blair had on Monday and he himself had on Tuesday, he said. "We just feel it would be very undesirable to leave next week drift on without making any progress. Equally we can't negotiate anything on our own. We need to carry the parties - all of them - with us, particularly those two who have difficulties," he said.
"The more we have talked since Tuesday night the more we convinced ourselves that we really need to try to put some momentum into this. I just hope everybody is of the same view."
He warned that those who believed the situation would be resolved by triggering the d'Hondt system for selecting an executive did not fully understand the situation. "Moving on the d'Hondt system does not give you an executive unless there is cross-community support," he said.
The executive could only be established when powers were devolved from Westminster and this would only happen when there was cross-community support, he said. "Clearly if the issue between the UUP and Sinn Fein is not resolved, then you can't achieve that," he said.