The DUP has warned against a concerted push by the two governments for an early deal to restore Stormont.
Mr Peter Robinson laid down a marker during an interview with the BBC, insisting any deal on devolution "would take time" and that it was more important to get the details of an agreement right than getting such a deal early.
He was speaking before a week of key engagements involving the Belfast Agreement review at Stormont, and more talks in London hosted by the Taoiseach and the British Prime Minister. Another visit by the US special envoy is scheduled before the end of the month.
Mr Ahern and Mr Tony Blair are to co-host a series of bilateral meetings with the Northern parties at Lancaster House in London on Friday, just before President Bush arrives in Ireland.
While no major breakthrough is expected, the governments want to highlight the progress made in the review so far and to look forward to a sustained effort in September to achieve a deal on the restoration of Stormont.
Sinn Féin has repeatedly voiced its concern that the Democratic Unionists are "playing a long game" in the hope of further electoral gains next year. Republicans have also criticised the DUP, whose leadership of unionism was strengthened after last week's strong performance in the EU election, for refusing to engage Sinn Féin in direct talks.
Mr Robinson, however, denies that the DUP is dragging its feet in the negotiations. He told the BBC it took years to negotiate the Belfast Agreement and correspondingly it could "take some time" to find accord on the changes he feels are necessary to any system of devolved power-sharing government.
His remarks coincide with the findings of a public attitude survey, co-ordinated by Queen's University, Belfast, and the University of Ulster. Researchers have reported growing disenchantment with the Assembly and rising acceptance of direct rule from London, especially among unionists.
Mr Robinson told Radio Ulster: "It is far better that we work slowly in building up this agreement, making sure that it's something that is lasting and stable, rather than simply rushing into it and taking something that's cobbled together and could collapse at the first difficulty that comes along."
His remarks are in marked contrast to warnings from the Sinn Féin president that his constituency would not put up with open-ended direct rule, nor would republicans settle for a diluted version of the Belfast Agreement.
Mr Gerry Adams has continued to stress the need for a deal with unionists.
He told his party's annual Wolfe Tone commemoration in Bodenstown, Co Kildare, yesterday: "The reality is that if the political will exists - and republicans have that political will - then we can all collectively make progress. Consequently, the intense efforts to agree a package must continue until there is an agreement or until we have exhausted all possibilities of agreement."
The Irish Times has been told by a reliable Sinn Féin insider that agreement on outstanding aspects of the accord can be achieved by the end of the year.
Government officials make clear that no breakthrough is expected at Lancaster House, but they are equally keen to talk up the prospects of further progress in the early autumn, subject to another peaceful summer on the streets of Northern Ireland.
Ulster Unionists believe the British government is keen to press for a deal between Sinn Féin and the DUP before the November 26th anniversary of elections to the Assembly.