The Taoiseach today blamed the Provisional IRA for the Belfast bank robbery which was carried out in December.
Speaking on RTE's This Weekprogramme, Mr Ahern said: "The Provisional IRA was involved. This was an IRA job...this was a job that was known to the political leadership."
Mr Ahern said he was upset that the crime was being planned when the Government was taking part in crucial talks over reaching a comprehensive agreement to restore the power-sharing executive.
"In a period of intensive talks, my information is now that people in very senior positions would have known what was going on."
But he said: "Ultimately we all have to be big enough to keep the peace process going forward. Going back to where we were in the past would be the wrong thing to do."
"We had finalised some very, very difficult issues during last year and we spent the entire of 2004 working to get to the 8th of December and at the end we had essentially been left with two outstanding issues which had to be resolved. One was the transparency issue over decommissioning of IRA weapons and the other was IRA criminality".
Mr Ahern said the Sinn Fein leadership could not agree over the wording concerning the issue of IRA criminality and that he must conclude it was because they knew "these kind of events were going on."
Yesterday Mr Ahern said the Provisional IRA will have to make "demonstrable commitments" to end all of its criminal activities.
The Sinn Fein TD Mr Caoimhghín Ó Caoláin said it was a disgrace that the Government had accepted without question the opinion of PSNI Chief Constable Hugh Orde on the robbery. He said Mr Orde "has produced not a scintilla of evidence to back his allegations".
At a press conference on Friday the PSNI blamed the paramilitary organisation for the £26.5 million Northern Bank raid.
Mr Ó Caoláin also said: "It is clear now that the DUP were unwilling to share power with republicans at this time".
The British Prime Minister has said Unionists were "entirely justified" in refusing to share power with republicans in the light of the robbery.
Unionists called on London to exclude Sinn Fein and press ahead with efforts to restore devolution without them.
Speaking on BBC1's Breakfast with FrostMr Blair said: "Unionism has accepted now that it must share power with republicans and nationalists. But it is entirely justified in saying it will not share power unless there is a definitive end to all forms of paramilitary activity or criminal activity by one of the parties that is associated with a paramilitary group."
He said it was still possible to move towards peace.
But he said: "It can't be 99 per cent giving up violence. And it certainly can't be 80 per cent giving up violence, it has got to be 100 per cent."
Additional reporting PA