The SDLP will not take part in an assembly without power, the party's deputy leader has said.
Alasdair McDonnell said he will not engage in playground politics
Alasdair McDonnell said his party was not interested in "an insulting invitation" to engage in "pre-school playground" politics.
He said there was no point in debating important matters if they had no power to alter government policy.
The parties have been invited to return to Stormont on 15 May in a bid to restore devolved government.
Members will sit for an intitial six-week session before rising for the summer.
Speaking on the BBC's Inside Politics programme, Dr McDonnell said the SDLP would accept Northern Ireland Secretary Peter Hain's invitation if the political parties were given powers to alter decisions taken by direct rule ministers.
"If Peter Hain is saying to us, 'Yes, I 'll allow you guys to make decisions on education and I'll allow you guys to reverse some of the decisions my ministers have taken', that's fine, then we will engage.
"But if it's just a question of having a pre-school play group then we have no interest."
A deadline to restore devolution by 24 November was unveiled in the "take-it-or-leave-it" plan, outlined by the prime minister and the taoiseach in Armagh.
Tony Blair and Bertie Ahern said the assembly would be recalled on 15 May with parties being given six weeks to elect an executive.
If that fails, the 108 members get a further 12 weeks to try to form a multi-party devolved government.
If that attempt also fails, salaries will stop.
The British and Irish governments would then work on partnership arrangements to implement the Good Friday Agreement.
Devolved government at Stormont was suspended in October 2002 following allegations of a republican spy ring.