The Taoiseach and British Prime Minister intend to travel to Northern Ireland on Wednesday either to endorse a comprehensive political agreement or to publish their proposals for restoring devolution if the deal is rejected.
The British Prime Minister, Mr Tony Blair, will hold a critical meeting with the Rev Ian Paisley in Downing Street this afternoon as both the DUP and Sinn Féin continue to wage a brinkmanship battle over visual verification of IRA disarmament.
British officials were last night arranging a Belfast venue for Wednesday's scheduled meeting between the Taoiseach, Mr Ahern, and Mr Blair.
Mr Ahern and Mr Blair were hoping for definitive answers from the DUP and Sinn Féin today to their amended blueprint for restoring devolution, but are prepared to give the parties until tomorrow evening for their final responses.
"Sinn Féin and the DUP have until close of business on Tuesday to tell us whether this is a runner or not," said a senior Dublin source last night.
"The parties had the weekend to reflect on our proposals. It's now up to them to make up their minds," said a British government spokesman.
Dublin and London sources made it clear, however, that if the blueprint was rejected, the governments would publish the proposals or a summary of them. They appeared confident that the public would consider the proposals a fair deal.
If the proposals are rejected, Mr Blair will be faced with the option of whether to call Assembly elections. In such an eventuality the "blame game" would then kick in with whichever party - the DUP or Sinn Féin - was viewed as chiefly responsible for the collapse of the deal having to justify its stance to the electorate.
Mr Blair and Mr Ahern hope that Wednesday will witness a carefully choreographed series of events in which the IRA will make a clear statement of its intent to end activity and disarm and that the DUP will respond with an equally transparent commitment to share power with Sinn Féin. As part of the agreement package the Government has conceded the Sinn Féin demand that Northern Ireland MPs and MEPS should have some speaking rights in the Dáil.
Other key issues yet to be fully resolved include establishing a clear protocol for how the DUP leader, Dr Paisley, and Sinn Féin's chief negotiator Mr Martin McGuinness would work together as First and Deputy First Minister.
The sequence for when the DUP would clearly illustrate it was prepared to share power with Sinn Féin was also an outstanding issue, sources added. But, it was generally agreed, the main obstacle to a deal was resolving the visual proof issue.
The governments' blueprint required photographs to be published after devolution was restored, while Dr Paisley would be allowed see pictures of decommissioning before devolution, it is understood.
Dr Paisley's most recent demand, however, was for publication of visual evidence after decommissioning but before the DUP was demonstrably sharing power with Sinn Féin.
While Dr Paisley so far has made the issue of photographs almost a bottom line demand for the DUP, Mr Adams yesterday strongly indicated that the IRA would not allow photographs to be produced or published. He appeared to characterise the visual requirement as an unacceptable attempt to humiliate republicans.
In an interview on RTÉ yesterday he referred to the current potential to achieve "an end to physical force republicanism".
In an implicit reference to the photographic demand he added: "Is it going to be thrown away because Ian Paisley does not get the process of humiliation that he wants?"
Senior DUP members held a meeting over the weekend to consider the governments' proposals.
A DUP senior delegation also met Gen John de Chastelain's decommissioning body on Saturday, after which Dr Paisley, his deputy Mr Peter Robinson, and North Belfast MP Mr Nigel Dodds complained that the IRA had not yet renewed contact with the general.