The Democratic Unionists will today press the Government to take action amid a political crisis in Northern Ireland's power-sharing government caused by claims the Provisional IRA still exists.
DUP deputy leader Nigel Dodds will lead a party delegation to meet Northern Ireland Secretary Theresa Villiers in Belfast to discuss the furore sparked by a recent murder in the city and a police assessment that PIRA members were involved.
The DUP's main electoral rivals, the Ulster Unionists, are set to resign from the Stormont Executive next week over the revelations.
Announcing the move on Wednesday, UUP leader Mike Nesbitt claimed trust in Sinn Fein had been shattered and his party has no option other than to withdraw from the five-party coalition and form an opposition in the Assembly.
Sinn Fein has accused the UUP of contriving a crisis in a bid to outflank the DUP ahead of next year's Assembly poll.
While the dramatic walkout by one of the three minor coalition partners will not automatically trigger the collapse of the administration, it does throw its future into serious doubt, as it mounts pressure on the DUP to follow suit.
If the DUP - Northern Ireland's largest party - left the Executive, it would fold immediately.
However, the party has not shown any immediate inclination to follow the UUP out the exit door.
Mr Dodds has accused the UUP of "hypocrisy", noting the party sat in an executive with Sinn Fein in times prior to IRA decommissioning.
He insisted the focus should be on republican wrong-doing, not unionist departures from government.
He said that his party would remind Ms Villiers of "the responsibilities she has to punish any party that is found to be in breach of their commitments to exclusively peaceful and democratic means".
"It is republicans who are responsible for the current situation and it is on republicans that the pressure should be maintained," he said.
"If anyone should be excluded from government in Northern Ireland for wrongdoing, it is Sinn Fein, not unionists.
"So there is a clear onus on the other Northern Ireland parties to recognise what needs to be done.
"The Secretary of State must recognise that action must be taken to ensure that government in Northern Ireland only consists of those committed to exclusively peaceful and democratic means."
No evidence the killing was sanctioned by the IRA
At the weekend, Police Service of Northern Ireland (PSNI) chief constable George Hamilton said that the IRA still exists, but is not engaged in terrorism - instead pursuing peaceful, political republicanism.
However, the PSNI also said some PIRA members were involved in the murder earlier this month of former IRA man Kevin McGuigan, 53, in co-operation with a group styling itself Action Against Drugs. Detectives said there is no evidence the killing was sanctioned by the IRA leadership.
Mr McGuigan was suspected by some in the republican movement of involvement in the murder of former IRA leader Gerard "Jock" Davison in the nearby Markets area of Belfast three months ago.
Police believe his killing was a revenge attack by Mr Davison's republican associates.
Mr Dodds added: "The DUP will not turn a blind eye to the implications of the chief constable's statement. If others do not act with us to punish the wrongdoers, then make no mistake we will do what is right for unionism and for Northern Ireland."
It is almost 20 years since the Provisional IRA's last ceasefire and a decade on from the supposed decommissioning of its weapons.
The UUP's one minister in an administration made up of 13 ministers and two junior ministers will resign next week if Mr Nesbitt's recommendation is supported by the party's ruling executive on Saturday - an endorsement that is widely expected.
An Ulster Unionist exit from the Executive would be highly symbolic given the party was one of the architects of the 1998 Good Friday peace agreement that paved the way for nationalists and unionists to share power.
The accord did not envisage an Assembly with an official opposition.