NI Secretary Peter Hain has invited all the main parties to take their places on a committee to restore devolution.
Parties must decide by next week on taking part in committee
The DUP and Sinn Fein have yet to state clearly whether they will join up. Mr Hain has said they have until next Tuesday to make their mind up.
It is thought the committee would have three members from the four main parties and two from Alliance.
Mr Hain also confirmed that Tony Blair and Bertie Ahern will hold talks with the parties before the summer break.
Speaking in London on Thursday, he said he wanted the committee to look at work that needs to be done in preparation for government.
Mr Hain revealed he had asked the assembly's speaker Eileen Bell to convene the first meeting of the committee on 6 June to prepare for the negotiations involving the two prime ministers.
He said participation in this committee will show how willing assembly members are to do the business of government.
"This is a sign as to whether the parties are serious about doing the work in the re-established assembly," Mr Hain said.
"If they are serious, then I believe they'll turn up. If they're not, the public will judge as to the value of the assembly."
Ulster Unionist leader Sir Reg Empey welcomed the initiative, adding that the make-up of the committee would "ensure adequate cross-community consensus".
"This committee prevents the DUP from running away from the substantive work that needs to be done in identifying the blockages that are standing in the way of the restoration of devolution," he said.
Sinn Fein's Martin McGuinness said his party would judge the committee "on its ability to contribute to the restoration of the power-sharing executive".
"We are not interested in a talking shop," he added.
On Wednesday, Mr Hain said the committee should not be a negotiating body.
He was replying to DUP leader Ian Paisley's concerns that the committee would be used as a negotiating forum.
Mr Paisley had said his party would not take part in talks running alongside those promised between the parties and the British and Irish governments.
While the DUP has been seeking to limit the role which the committee plays, the SDLP said it would only enter it if it was clear "that it is the vehicle for restoration of the agreement's institutions, not a talking shop or meaningless sideshow".
The DUP continues to refuse to enter direct dialogue with Sinn Fein. However, in the old assembly, DUP members took part in committees alongside republicans.