DUP leader Peter Robinson is expected to ask the British government to stall the return of Stormont as he seeks a fresh rounds of all-party talks.
The First Minister will travel to London today to meet Prime Minister David Cameron about the latest crisis to engulf the devolved institutions.
The UUP's Danny Kennedy is set to tender his resignation as regional development minister in protest at the continuing involvement of Sinn Féin in government.
The Stormont executive was plunged into uncertainty almost a fortnight ago when the PSNI said members of the IRA were involved in the murder of Kevin McGuigan in Belfast's Short Strand on August 12.
Unionists have called for Sinn Fein's exclusion from the power-sharing executive.
In his first public appearance since the crisis broke, Mr Robinson called last night for a fresh round of intensive negotiations about Stormont's future.
He appeared to indicate that he hopes to keep the devolved institutions alive, though only after a new conditions for government have been agreed.
"We now have to deal with the relationship with paramilitary organisations and membership of the executive," Mr Robinson said.
"I believe we need a proper intensive talks process to see if those issues can be resolved because if they are not resolved there isn't a firm basis for us to proceed with government."
Mr Robinson has accused Ulster Unionists of political expediency ahead of assembly election due next year, but also warned that it cannot be "business as usual" with Sinn Fein in the coming weeks.
It is understood he will ask Mr Cameron to extend the assembly's summer recess, while keeping the executive in place.
Secretary of State Theresa Villiers will meanwhile meet the Republic's Minister for Foreign Affairs Charlie Flanagan to discuss the ongoing crisis.
