The end of May has been identified by the Taoiseach as the most likely time for holding the proposed referendum to amend Articles 2 and 3 of the Constitution.
It is now expected that polling day will be in the 'latter part' of the month because of the '30-day rule', which dictates that the Dail be permitted to consider and debate the text of the Bill allowing for the referendum.
Dismissing the prospect of a referendum on May 8th, Mr Ahern said procedures in the House of Commons also made the earlier date less likely.
Meanwhile, publication of the proposed amendment will only occur 'if we can reach agreement', he added. 'We would have to have a separate referendum Bill in this House and if its wording is agreed by the other parties, it would be appropriate to debate it in the House.'
Asked if he envisaged the Dail being asked to give its assent to changes to Articles 2 and 3 in advance of any final settlement being negotiated by the parties in the Northern Ireland talks, Mr Ahern said: 'I hope the agreement is completed within the talks with the British government.'
Expressing anxiety over the Parades Commission, the Taoiseach said he had always supported the body because 'an independent assessment and authoritative judgment made in a neutral and fair fashion is the correct way to proceed'.
'I am concerned about this matter, particularly having regard to concerns emanating from all levels of the nationalist community at the perceived lack of balance within the Commission because of the latest appointments,' Mr Ahern said.
Regardless of the individuals involved, public perception was vitally important to the work of this body in the future.
Both governments had spent a great deal of time recently discussing constitutional, institutional, policing and equality matters and were trying to press ahead to reach agreement by Easter. However, they must have the agreement of the parties on these issues.
'Rather than placing the whole agreement before the parties and then discovering there are enormous differences to be resolved, we are trying to narrow down matters into different sections such as constitutional, institutional, policing and equality matters', he said.