The British and Irish governments and Sinn Féin remain at odds over the amount of progress in the negotiations to restore devolution as the Taoiseach and British Prime Minister prepare for a Downing Street meeting today.
Mr Ahern and Mr Blair will assess the prospects of striking a deal to reactivate the Stormont institutions when they meet with the pro-Belfast Agreement parties in Hillsborough on Monday.
The leaders will discuss whether to present the parties on Monday with an implementation plan to reinstate the Executive and Assembly, or whether they should first directly consult the parties to determine if such an initiative would be productive.
Senior Sinn Féin politicians complain they have no clear view of what the British government will do to implement outstanding elements of the agreement.
In response, Dublin and London sources insist that substantial progress has been made on key issues such as demilitarisation, policing, devolving criminal justice to the Assembly and offering an amnesty for IRA fugitives - the "on the runs", or OTRs. They repeated they still did not know what was the "IRA's bottom line".
The British and Irish governments have completed most elements of a package, which they believe all parties, including Sinn Féin and the IRA, could endorse, according to the sources. Between now and Monday British and Irish officials would try "to tie up any loose ends", they added.
The Minister for Foreign Affairs, Mr Cowen, and the Northern Secretary, Mr Paul Murphy, will remain in contact in the coming days as their officials try to complete an implementation plan that addresses the concerns of all the parties.
There is doubt, however, over whether Mr Ahern and Mr Blair would be in a position to present a finalised document on Monday morning. "That is what we are working to. The Taoiseach and Prime Minister certainly will have the framework of a deal but may meet the parties first before deciding to produce their final paper," said one source.
Dublin and London sources repeated that their great difficulty was the refusal by republicans to state clearly what the IRA would do to reciprocate movement on demilitarisation, policing, criminal justice, "on the runs" and other issues.
UTV reported last night that the British government is to establish a judicial commission whereby "on the runs" would receive convictions, but not serve any period in prison. They would be effectively released on licence as with all other prisoners let out under the early release scheme of the Belfast Agreeement.
Sinn Féin continues to be sceptical. "We have nothing before us that would suggest we are dealing with a British government that is intent on implementing the Good Friday agreement fully and faithfully. The goods have not been produced," a senior party source said.
If the St Patrick's week deadline was to be met, agreement should be concluded in the next week to 10 days, he added. British and Irish sources said the timeframe for agreement was far shorter.
The Sinn Féin figure claimed: "The least problematic issue is the attitude of republicans in terms of securing the peace process."
He refused to be specific on whether the IRA would verifiably illustrate that it was no longer active, but said, "I would hope we could construct a set of circumstances in which all armed groups recognise the pre-eminence of politicians and the political process."
