Tony Blair and Bertie Ahern have discussed their latest blueprint for the NI Assembly's restoration on the margins of an EU summit in Brussels.
The two PMs held talks in Brussels
They said they intend pressing ahead with plans to restore the assembly.
It is understood the British and Irish prime ministers are planning to visit NI in April to unveil their proposals.
Irish sources said the visit was pencilled in for 6 April. Mr Ahern said he believed the conditions were now right to allow for political progress.
"The process has moved forward to an incredible extent over the last period of time," he said.
"IRA weapons are a thing of the past and hopefully the IRA is moving that way too.
"There is a moment of opportunity coming up which should not be allowed to pass and may not come around for a long time again."
DUP deputy leader Peter Robinson said: "I do not want the government to be under the misapprehension that by forming
a lower level of devolution and timetabling it for full executive devolution, then at that point there will automatically be executive devolution.
"If that can be done, there will be no-one happier than I. If the transformation takes place, I might be surprised but at least I will be content."
British and Irish officials are in daily contact on the details of the plan to revive the Stormont assembly.
It is believed the governments intend to call the parties back to Stormont for a six-week period prior to the summer marching season.
BBC NI political editor Mark Devenport said: "There is little expectation that the politicians will be able to form a power-sharing executive, but officials are considering emergency rule changes which would enable assembly members to conduct some work.
"Under the current procedures, David Trimble and Mark Durkan would be reinstated as acting first and deputy first minister - something any new rules will almost certainly change.
"Political sources suggest that the assembly would break over the summer and then reconvene in September.
"There are different estimates of how long the politicians might be given to form an executive - some sources say October will be a cut-off date, others indicate the deadline will be the end of the year."
Devolved government at Stormont was suspended in October 2002 following allegations of a republican spy ring at the Northern Ireland Office.
However, doubt was cast on that after a senior Sinn Fein official acquitted of involvement said he had been a British agent for 20 years and that there was no spy ring.