The Taoiseach has signalled that agreement on a new European constitution is unlikely to be reached during Ireland's presidency of the EU.
Mr Ahern told the Dáil that "no presidency can compel agreement if the political circumstances are not right. I am certainly not going to promise that the Inter-Governmental Conference (ongoing treaty-making process) will finish in our presidency."
But "equally, it would be premature to conclude that it will not. If there is good reason to believe, in the light of my consultations, that faster progress is possible, then I will spare no effort to achieve it."
During a debate on the EU council meeting which floundered over new voting arrangements, Mr Ahern said "there was a strong sense that more time would be needed. Certainly, the situation is complicated by the electoral calendar, not least the European Parliament elections in June."
Former Taoiseach Mr John Bruton, who was EU president in 1996, said Ireland's presidency would be the "greatest ever" if Mr Ahern could persuade European leaders to reach agreement on a constitution. The Fine Gael TD said that while the Taoiseach had "lowered expectations" he could work around this.
Labour leader Mr Pat Rabbitte said the Taoiseach's comments at the weekend, and those of Minister of State Mr Dick Roche, showed they both regarded the challenge as a "poisoned chalice, or at least a cup that they wished to pass from them as soon as possible".
There were "real grounds for concern in the image so far created that the entire Government seems prepared to twiddle its thumbs throughout its presidency".