The Northern Secretary, Dr Mowlam, has set early March for completion of the legislative process leading to the transfer of powers to the institutions set up under the Belfast Agreement.
A spokesman for the Northern Ireland Office said the precise date would be confirmed later.
In a series of meetings yesterday, Dr Mowlam outlined to the parties the legislative programme between now and March that will be necessary to allow devolution to take place.
A transfer of powers by Dublin to the new North-South bodies will also be required. However, until the issues of decommissioning and formation of an executive have been resolved, the formal transfer will not happen.
But now the parties have been presented with an "indicative time-scale" for addressing and resolving these difficulties. The meetings with the parties continue today.
The Alliance Party was the first to meet Dr Mowlam yesterday. Its leader, Mr Sean Neeson, said March 10th was "more or less" the deadline for devolution.
"There is a good deal of work now going on between the officials of the British and Irish governments, and quite clearly the date of March 10th has now more or less been established as the date when powers will be transferred to the Northern Ireland Assembly. We welcome the fact that this work is going on behind the scenes."
Recalling that there had been other deadlines in the past and that the October 31st target date for agreement on North-South bodies had not been met, he said: "If we all pull together and want to make sure that the Assembly works, I think that deadline can in fact be met."
Mr Peter Robinson of the DUP said after his party's delegation met the Secretary of State: "The timetable which she has provided makes no provision for its slipping because of a failure on the part of the IRA to decommission, nor does it take into account whether there is approval in the Assembly or not.
"Her timetable proceeds even without approval and, when that specific question was put to her aides, her aides said, very clearly, that if there was approval it would provide a firmer foundation, but the implication was clear, that she proceeds even without approval next week in the Assembly, that she will still set up the 10 departments. She will still put all the functions into those 10 departments and start exercising those 10 departments in Northern Ireland."
Sinn Fein's chief negotiator, Mr Martin McGuinness, emerged from his party's meeting with Dr Mowlam at Castle Buildings to say that he believed a shadow executive could be set up as early as next Tuesday or Wednesday.
Earlier the First Minister-designate, Mr David Trimble, outlined a scenario where, if the IRA refused to decommission, Sinn Fein would have to remain in opposition.
"It is not a choice between decommissioning and failure of the Assembly," he told PA News. "If IRA decommissioning is not achieved, then the Ulster Unionists can go on without Sinn Fein, and form an executive with the DUP and SDLP."
Mr Trimble said he did not believe Sinn Fein had tried its hardest to get the IRA to disarm, but there was still time. He was optimistic the executive could be in place by mid- to late March.
Mr Trimble said he was very encouraged by Mr Tony Blair's recent article in the two Belfast morning papers, stressing that decommissioning would be the key confidence-building step.
"All the political decisions have been taken. The only area where there hasn't been any progress is decommissioning, and the Prime Minister made it clear there is an obligation on Sinn Fein to use their influence to bring about actual decommissioning.
"Either they haven't used their best efforts so far or these have proved fruitless, and I don't think anyone believes the latter," he said.
The Sinn Fein vice-president, Mr Pat Doherty, called on Mr Trimble to show "real leadership." He added: "The recent boyish behaviour that Trimble displayed when he launched a barrage of insults at Gerry Adams does not appear to emanate from someone who has the ability to treat all participants in the current talks with impartiality."
Mr Doherty said the time had come for Mr Trimble "to stand up to the bully-boys in his party and fulfil his obligations by ensuring that the Good Friday agreement is implemented in full and to the letter."
The Workers' Party president, Mr Tom French, said the Assembly should set the agenda for a new Northern Ireland on issues such as employment, education and health services.
Dr Mo Mowlam: outlined legislative programme