Ireland's EU presidency has cost an estimated €60.23 million, the Taoiseach told the Dáil.
Mr Ahern said that was the amount required by all Departments and agencies, and included the cost of official meetings, travel abroad, hospitality in Ireland, security arrangements, cultural presentations in Ireland and Europe, information services and the presidency website.
"The presidency has been managed with a view to economy and efficiency while fully meeting the expectations of partners. The Irish presidency has gratefully accepted sponsorship from Irish and American companies to reduce overall costs."
He added that in his own Department, about €2 million would be required to meet costs, although it was not possible yet to indicate total costs or their final distribution between the various Departments.
Replying to a series of questions, Mr Ahern said it appeared that some time next year would be the appropriate date for the referendum on the EU constitution.
He rejected Opposition challenges to his claim that he would have had adequate support for the presidency of the EU Commission if he had wanted the post.
The Fine Gael leader, Mr Enda Kenny, said he commended the Taoiseach on having found a very suitable candidate in Mr Jose Manuel Barroso.
"Far be it for me to say that The Irish Times could ever be wrong, or that somebody from the Department of the Taoiseach might have been a little loose with words. However, on July 6th The Irish Times clearly reported the Taoiseach's words that he was tempted when 21 of his colleagues around the table said he could have had the job quite easily.
"Therefore, only three leaders did not support the Taoiseach. Either I am dealing with a bunch of leaders who do not understand what the truth is or somebody has become very imaginative with words.
"I attended a number of EPP meetings with 11 prime ministers and, with the greatest of respect to the Taoiseach, at no stage was his name mentioned."
Mr Ahern said he had made his position clear to his colleagues before the European Council and during the round of meetings he had with them.
"It was there that they clearly stated their positions. The one person from the EPP group who did not support me did so for a different reason as he had strong views in supporting a present commissioner, who, by the way, is not part of the EPP group. So none of the deputy's people pushed EPP members. The negotiator and leader of the deputy's EPP group put considerable pressure on me, which I appreciated."
The Labour leader, Mr Pat Rabbitte, said he thought the PES would support the Taoiseach.
"Like Deputy Kenny I could not find much of a trace of that at the meetings. It is obvious that there must be some prime ministerial protocol that says they should not report it back to their groups."
Mr Joe Higgins (Socialist Party, Dublin West) said: "Europe is full of closet Fianna Fáilers, obviously."
