Political crisis talks in Northern Ireland are due to start again on Monday.
Arlene Foster will today take the reins in her first day as the sole unionist in Northern Ireland's faltering power-sharing government.
She was named acting first minister after the mass resignation of her party colleagues amid a crisis sparked by a murder linked to members of the IRA.
The senior Democratic Unionist told BBC's The View: "I have been placed there as a gatekeeper to make sure that Sinn Fein and the SDLP ministers don't take actions that will damage Northern Ireland and principally, let's be honest, that damage the unionist community.
"If anybody knows me and indeed knows the Democratic Unionist Party they know that I'm not going to put at risk to the people of Northern Ireland the possibility that rogue Sinn Fein or renegade SDLP ministers are going to take decisions that will harm the community in Northern Ireland."
DUP leader Peter Robinson stepped aside as First Minister over unionist concerns about paramilitarism - Sinn Fein contains many former IRA members - and has asked Mrs Foster, his finance minister, to remain in the Executive to prevent nationalists from taking over key ministerial posts.
But her remarks drew criticism from Sinn Fein's Gerry Kelly, who described them as "bigoted" and a "throwback" to the past.
He told the broadcaster: "To make this attack on nationalism - because it wasn't just republicanism, but on nationalism - and call ministers 'rogue ministers' is a complete nonsense."
The unionist walkout from the mandatory coalition came after the DUP failed to get the Assembly adjourned for a period to allow crisis talks to address the implications of the murder of Kevin McGuigan.
The political furore over the killing intensified on Wednesday when three senior republicans were arrested in connection with the murder. The trio and a woman have been released unconditionally, police said.
As he announced the resignations, Mr Robinson repeated a demand for the Government to suspend the institutions outright to enable space for the talks to happen. Northern Ireland Secretary Theresa Villiers last night rejected the call.
The fallout from the murder of Mr McGuigan has already seen the Ulster Unionists resign their one ministerial post.
The exit of Mr Robinson along with three of the DUP's four other ministers, and its one junior minister, has left the 13 minister administration in free fall. The departments of health and social care; social development; enterprise, trade and investment; and regional development are now effectively rudderless.
Collapse of power-sharing is not inevitable but the crisis follows a day of dramatic developments at Stormont on Thursday. Mr Robinson has bought the institutions and negotiators a limited period to find a resolution.
The DUP wanted all Assembly business suspended to allow crisis talks to take place. The leader's announcement came after Sinn Fein, the SDLP and the Ulster Unionists voted against a DUP proposal to adjourn the Assembly.
He issued a resignation ultimatum on Wednesday after the arrest of republicans Bobby Storey, Eddie Copeland and Brian Gillen over the fatal shooting of Mr McGuigan.
Police have said current members of the IRA were involved in last month's shooting of Mr McGuigan in a suspected revenge attack for the murder of former IRA commander Gerard "Jock" Davison in Belfast three months earlier.
The disclosures about the IRA have heaped pressure on Sinn Fein to explain why the supposedly defunct paramilitary organisation is still in existence, even if for what police described as peaceful, political purposes.
Ms Villiers said re-instigating an independent authority to look at decommissioning command structures was one of the most "credible" options.
She told BBC Radio 4's Today programme: "I think that is certainly one of the most credible ideas. I think it wouldn't necessarily be appropriate to set up exactly the same structure that existed in the past and certainly one would need to ask it a different question. In the past the question was just about decommissioning and ceasefires.
"I think now it is very clear we want to see these paramilitary organisations disband altogether. We also want to investigate the role of members of these organisations in relation to criminality."
The Northern Ireland Secretary said it was "inevitable" that power-sharing would come under "huge strain".
She said: "I certainly wish that the DUP had been able to find a different way to deal with this situation but I also accept that it had put a huge strain on working relationships as it would in any situation where a leading figure in your coalition partner is arrested in relation to a murder case.
"That poses very real difficulties and very real strains so I am afraid it's inevitable that that was going to have a very significant impact on power sharing."
Ms Villiers called on Labour's new leader, to be named on Saturday, to continue the "bipartisan approach" on Northern Ireland.
"I think it would be gravely destabilising if a Jeremy Corbyn led Labour party decided to depart from that," she added.
Former first minister Lord Trimble said the unionist resignations were an attempt to force the UK government to take action and called for the Independent Monitoring Commission to be brought back.
He told the Today programme: "It looks to me very much as though we are back to the terrible situation we were in in 1998 when the Secretary of State for Northern Ireland in a similar situation said 'oh, these killings were just internal housekeeping by the Republican movement', in effect giving them a licence to murder."
Asked about Mr Kelly's claims that the IRA did not exist and the people involved were criminals, the peer said: "He should know because they are his people that he is talking about."