Northern Ireland’s first minister, Arlene Foster, has said she is willing to open talks with Sinn Féin to prevent a collapse of power sharing in the region next week.

Her comments came as it emerged that Sinn Féin’s Martin McGuiness is expected to make a second statement about his future, following his announcement on Monday that he is resigning as deputy first minister.

Foster said she was willing to support a public inquiry into a botched green energy scheme that will cost taxpayers up to £500m and has triggered the current political crisis.



But the Democratic Unionist party leader said she was not afraid of elections to a new Northern Ireland assembly, while acknowledging that any campaign would be rancorous and “brutal”.



Speaking at DUP headquarters on Tuesday afternoon, Foster said she had been “disgracefully maligned in a most vicious manner” over allegations surrounding the renewable heat incentive (RHI). She said there was still room for optimism if an inquiry into the scheme could begin by the end of the week. “It is of the utmost importance that the truth comes out,” Foster said.

The first minister described McGuinness’s resignation as “not principled.” However, she still held out the prospect of talks aimed at averting an election that her party colleague Jeffrey Donaldson warned would not necessarily lead to a new devolved government being formed. Foster said: “We are willing to take part with any discussion to see if a way forward can be found.

“I remain open to further discussions with Sinn Féin or any of the other parties in the assembly over the next few days.”



Earleir, sources in Dublin said McGuinness is considering whether to stand in the expected elections to the Northern Ireland assembly.



McGuinness resigned in protest at Foster’s refusal to stand down temporarily while a public inquiry took place into the “cash for ash” scandal that has rocked the power-sharing government.

The RHI was set up by Foster in 2012 when she was enterprise minister, and was devised to increased energy consumption from renewable sources. However, non-domestic users, such as farmers, received subsidies far in excess of what they paid for heating.

While Foster has been under fire over the RHI, McGuinness and Sinn Féin have had to field questions about his apparent ailing health.



“He did say he would be making a second statement soon on his plans for the forthcoming election, but given his condition, it is expected he will not be standing this time around,” a senior source said.

But others in Derry said his decision was hanging in the balance because Sinn Féin was “short of big hitters”.

McGuinness denied that his decision to resign had anything to do with his health, but senior sources in Dublin said a report on RTÉ that he had a rare condition affecting the heart and central nervous system could help determine whether he would stand in the second election to the assembly in less than a year.



If McGuinness stands down from the assembly seat of Foyle in his native Derry, Sinn Féin would have to choose a new leader in the next assembly. The frontrunners to fill his position and possibly become deputy or even first minister would be the former Newry and Armagh MP, and ex-IRA prisoner, Conor Murphy, or Sinn Féin’s minister of health, Michelle O’Neill.



O’Neill appeared on Radio Ulster on Tuesday morning to criticise the DUP’s handling of the crisis. “Sinn Féin will not tolerate such incompetence and corruption,” she said.

Until McGuinness’s resignation, Sinn Féin had been under fire from opposition parties over its refusal to back a motion before Christmas declaring no confidence in Foster.



Sinn Féin was the DUP’s sole partner in the power-sharing government. Under the unique rules of devolution in Northern Ireland, if either of the two principal political leaders in the province resigns from office, the coalition falls and an election must be called.



Making a statement to MPs in Westminster, the Northern Ireland secretary, James Brokenshire, said: “I am in no doubt that what Northern Ireland needs at this time is strong, stable, devolved government, not a collapse of the institutions.

“[Recent political stability] has been hard gained and it should not be lightly thrown away.”

The Northern Ireland secretary, James Brokenshire, speaks in the House of Commons about the political situation. Photograph: AFP/Getty Images

Brokenshire said he had been in discussions with Sinn Féin and the DUP, as well as opposition parties in Northern Ireland and the Irish government, and was about to return to Belfast to seek a resolution to the crisis.

However, he warned MPs that with Sinn Féin having said it would not nominate anyone to replace McGuinness, if nothing happened within a week, he would be obliged to call assembly elections to take place within “a reasonable period”.

“As things stand, therefore, an early assembly election appears highly likely,” Brokenshire said, calling the situation “grave”.

The shadow Northern Ireland secretary, Dave Anderson, appealed to all parties in the assembly to try to avoid what is likely to be a highly divisive election, and “just keep talking to see if there is another way out of this”.

On the refusal by the DUP and Foster to stand down, Anderson said: “The DUP have to be convinced that they have a wider responsibility not just to themselves and Northern Ireland, but also to the UK as a whole.”



The Ulster Unionist party, which sits on the opposition benches, predicted that with the assembly’s imminent collapse, the DUP-Sinn Féin executive would be unable to set a budget for the financial year. It predicted redundancies in the state and community sector as a result.



The UUP assembly member Philip Smith said: “The consequences of such a scenario would be profound. Staff in those community groups dependent on support from government will shortly be given protective redundancy notice, the crisis in our health service will further deteriorate, as vital funding decisions are abandoned, and there could be a devastating 7% in-year cut to public services.”