SDLP leader Colum Eastwood has signalled his party's intention to attempt to form an official opposition at Stormont.
The Stormont institutions have been in flux since February when the DUP withdrew its first minister from the devolved executive, calling for the UK government to act on the Northern Ireland Protocol.
Jeffrey Donaldson's party has remained firm, resisting a number of attempts to resuscitate the power-sharing institutions.
The assembly will sit tomorrow to attempt for the third time since May's election to elect a new speaker following a recall motion by the SDLP.
However the DUP has made clear it will continue to block the election of a speaker.
Without a speaker, no further assembly business can be done, including the nomination of new first and deputy first ministers.
Mr Eastwood said he has written to the outgoing speaker Alex Maskey signalling his party's intention to form an official opposition ahead of the recall.
He has also formally nominated South Belfast MLA Matthew O'Toole as leader of the opposition.
Mr Eastwood said his party wants to provide a "constructive alternative to the politics of division, deadlock and failure that has gripped this place for far too long".
"We will provide a new kind of politics that addresses the problems facing parents and families across our communities," he said.
"The SDLP team will hold the provisional executive to account and provide a radical alternative to the politics of failure.
"Ministers and politicians taking home full salaries cannot be allowed to hide or fail to account for their decisions while families and businesses across the North struggle to make ends meet."
Mr O'Toole said their first act as opposition will be to recall the assembly.
"The SDLP has a plan, we have a fully drafted emergency bill that could unlock the millions of pounds resting in Stormont ministers' bank accounts and instead put it directly into families' pockets," he said.
"It's long past time that ministers collecting their wages showed us exactly what the public are paying for.
"The pretence of governing, while delivering nothing for people and communities, must end."
Mr O'Toole said the SDLP has not asked other parties to join its opposition and said that it is "for other parties to decide how they approach the outcome of the election".
He said that the inability to form an Assembly three months after the election is "hugely frustrating" for people in Northern Ireland.
Speaking to RTÉ's News at One, Mr O'Toole said: "What we want to do is provide constructive opposition to that kind of deadlock and division, for example on the cost of living crisis, but also on the crisis we face in the health service.
"What we're doing now is taking responsibility that we've been given, to form a constructive opposition at a time when the DUP is blocking the formation of not just an Executive, but an Assembly.
"There's been years of deadlock and division at Stormont, so what we're going to try and do is form a constructive opposition to that."
