DUP leader Ian Paisley has said it is nonsense to say the NI executive will be formed before the summer.
Ian Paisley has poured cold water on the notion of assembly recall
This follows speculation the British and Irish prime ministers will set a deadline for efforts to restore the assembly later this week.
Political sources have told the BBC assembly members are to be called to Stormont on 15 May for a six-week period to try to form an executive.
Mr Paisley said the foundations for such decisions had not been laid.
"I don't know what they're going to do, " he told the BBC's Sunday Sequence programme.
"I have read the papers, I have read all the conflicting reports from various politicians who think they know, and to say that they're going to call the assembly together to try to get an executive set up is absolutely nonsense.
"They can't do that, and it's not going to happen because the foundation for such a decision is not even laid and the foundation, of course, must be the end of terrorism."
Mr Paisley, whose party has suggested the formation of a shadow assembly, is due to meet Tony Blair on Tuesday.
"I think we are not going to have an executive but why do they not turn the assembly into a body that has power to consider important matters?" he said.
However, SDLP leader Mark Durkan has said the DUP should not have a veto over devolved institutions.
Speaking at the Irish Labour Party's annual conference in Dublin on Saturday, Mr Durkan said: "The DUP have rights under the agreement. They do not have rights over it."
He added: "I would love to be able to say that I see more positive potential in the latest proposals from the two governments than I currently do.
"The SDLP encourages them to be firmer and go further.
"We have to hope that what the taoiseach and prime minister announce on Thursday will not just be the source of shadowy assembly that would be right up the DUP's street because that could only lead to a dead end."
Meanwhile, Sinn Fein's Gerry Kelly reiterated his party's opposition to a "shadow assembly".
He said Sinn Fein would not take part in such body as the DUP would be able to dominate its committees.
Earlier this week, BBC Northern Ireland political editor Mark Devenport said the assembly would break for summer before being recalled in September for 12 weeks until the end of November.
He also said the political parties have been told the British and Irish governments are considering holding more talks at a stately home during the summer recess to deal with outstanding problems.
An emergency bill is expected to be put through Westminster to change some of the Stormont rules.
News of the deadline followed a series of talks between the Irish premier and some of Northern Ireland's political parties in Dublin on Thursday.
Devolved government at Stormont was suspended in October 2002 following allegations of a republican spy ring at the Northern Ireland Office.