The Taoiseach, Mr Ahern, and the British Prime Minister, Mr Tony Blair, have signalled their determination to conduct a "short, sharp and focused" review of the Belfast Agreement, beginning in January.
During an afternoon of bilateral talks with the leaders of the four main pro-Belfast Agreement parties in Downing Street, it is understood the Alliance Party submitted detailed proposals for changes in the Stormont Assembly's cross-community voting rules designed to break the political stalemate threatened by the Democratic Unionist Party's election success.
And Mr Ahern emerged from the talks last night to insist "there is absolutely no disagreement" between London and Dublin over the publication of Mr Justice Cory's report on alleged security force collusion in four controversial murders within the British jurisdiction.
With the Irish Government set to publish Judge Cory's report on two other cases today, Mr Blair told a Downing Street press conference that the two governments were operating to different timetables because they were involved in "different processes".
British sources later confirmed that a complex legal debate about the implication of Judge Cory's report was taking place behind-the-scenes, with a particular focus on obligations to individuals under the European Convention on Human Rights. Debate was also focusing on the need not to prejudice any criminal proceedings in respect of any of the cases considered.
Mr Blair said that the commitments he had previously given - in respect of publication of Judge Cory's report, and the ordering of any public inquiries recommended by him - still stood.
However, that was seriously challenged by the SDLP leader, Mr Mark Durkan, and by the Sinn Féin president, Mr Gerry Adams.
Mr Durkan said he had registered his party's concerns about the British government's "lack of movement" on the issue, and Mr Blair's inability to provide a timetable for publication.
Meanwhile, a plainly unhappy Mr Adams said he was leaving Downing Street "disappointed" and "not assured ... or reassured" as to why the British government was not proceeding with publication of the Cory report - or with other commitments set out in the Belfast Agreement and the British Irish Joint Declaration.
One Whitehall source suggested that Mr Adams's demeanour was perhaps explained by a "fairly blunt" meeting during which Mr Blair apparently said that Dr Paisley's ascendancy was not the sum total of the political problem facing Northern Ireland, and that the failure to deliver convincing IRA "acts of completion" had "undermined moderate unionism".
That was Ulster Unionist leader Mr David Trimble's message when he arrived for his meeting with Mr Blair and Mr Ahern.
However - while acknowledging that decommissioning had arisen in the context of "the unfinished business" of the failed October negotiations - Mr Adams said Mr Blair had not suggested the election result was because there was insufficient "transparency" about the IRA's third decommissioning act.
When asked if he could "do business with the Rev Ian Paisley", Mr Blair indicated he would do business with anyone on the basis of power sharing, justice and equality. He and Mr Ahern indicated they would signal their timetable for the review of the agreement early next month.
Mr Blair said: "I think the general consensus is that there should be a short, sharp and focused review." Mr Ahern agreed it should be "as short as possible".