The Taoiseach and the British Prime Minister will attempt to save the peace process when they meet at Downing Street on Tuesday.
There is a growing expectation that the position paper from the two governments on implementing all aspects of the Belfast Agreement will be published after this latest round of meetings, possibly late next week.
The document is also expected to set parameters for re-establishing the political institutions and decommissioning paramilitary arms.
Officials from the Irish and British governments have been meeting over the last week to identify ways of closing the gap between the UUP and Sinn Fein before the May 22nd decommissioning deadline in the Belfast Agreement.
A Government spokesman said last night that the two sides were "still looking at ways to move the process forward".
As part of this process, Mr Ahern and Mr Blair will meet on Tuesday with representatives of the main Northern parties, including the Ulster Unionist Party, the SDLP and Sinn Fein.
The Minister for Foreign Affairs, Mr Cowen, and the Northern Ireland Secretary, Mr Peter Mandelson, will also attend the Downing Street meetings.
Meanwhile, it emerged yesterday that the leader of the Unionist Party, Mr David Trimble, could be invited to address a joint sitting of the Houses of the Oireachtas should the Northern Ireland Assembly be re-established.
The Taoiseach has indicated that he would consider the proposal made by the Workers Party at a recent meeting.
It is also included in the party's policy document on the North which was published yesterday.
Such an invitation would see Mr Trimble join the small group of leaders, including Mr Blair and the US President, Mr Clinton, who have addressed special joint sittings of 166 TDs and 60 senators.
The former Workers Party TD Mr Tomas Mac Giolla said the Taoiseach had told their delegation that it was important to give Mr Trimble some forum in the Republic to present his ideas.
Mr Mac Giolla said that "anti-unionist feeling" in the Republic had increased in recent times.
An invitation to address the Oireachtas would be a "wonderful opportunity" for the Ulster Unionist leader to speak directly to all of the Irish people as well as being "a positive declaration that the people of Ireland are at one with him in the struggle for democracy".
A spokesman for Mr Trimble told The Irish Times that he would first prefer to see the proposal but that it would be considered like all invitations.
However, Mr Eoghan Harris, who advises Mr Trimble, said it was an "excellent and original idea".
He said it would allow Mr Trimble to outline his vision for relations between the North, the UK and the Republic.
Among the other proposals in the Workers Party document was that the Northern Ireland Executive be re-established immediately alongside a "credible, verifiable timetable for all paramilitaries to disarm".
The party also called on the paramilitary groups to reappoint their interlocutors to General de Chastelain's Commission on decommissioning.
The discussions in London will follow the format of discussions, also held in Downing Street prior to Easter, with separate meetings with each party.
Despite growing doubts about the likelihood of achieving the May 22nd deadline, Government sources were hopeful that the detail in the position paper would signal a breakthrough which would allow the Executive and Assembly to be re-established.