Sinn Féin president Gerry Adams has offered some qualification to his precondition that Arlene Foster cannot be part of the next Northern Executive until the public inquiry into the Renewable Heat Incentive (RHI) scheme is completed.

Mr Adams indicated that if the public inquiry to be chaired by retired judge Sir Patrick Coghlin addressed matters in “modular form” then the issue of the DUP leader’s alleged culpability over the cash for ash fiasco could be dealt with before the full inquiry was completed.

“There are ways of an inquiry coming forward in modular form, dealing with pertinent issues, so there are ways of sorting all of those matters out. It’s a very common sense position,” Mr Adams said at a press conference on the Falls Road in west Belfast on Saturday evening.

“We have never said that Arlene Foster needs to steps aside before negotiations happen. Arlene Foster is the leader of the DUP and we accept that absolutely,” he said.

“It isn’t that we are putting up absolute positions or red line positions, we are simply saying there is a scandal; there is a huge question over the loss potentially of half a billion of taxpayers’ money. Let’s get that sorted out, but that is not a precondition to negotiations beginning on Monday if the DUP are up for that,” said Mr Adams.

“What we have said is there is a need for this investigation or inquiry to come to conclusions before we could nominate her for the position of First Minister, and that remains our position,” he repeated.

While Judge Coghlin has indicated that he will not be issuing a preliminary report, Mr Adams opened up the possibility of the judge changing his mind and first reporting on the issue of whether or not the DUP leader must carry responsibility for the RHI fiasco.

This could have a bearing on the expected coming talks on how to restore Stormont between the DUP and Sinn Féin and the other parties.

Currently Sinn Féin is insisting Ms Foster can’t be First Minister until the matter of her “guilt or innocence” is decided.

The DUP so far equally is adamant that Ms Foster must be First Minister. If both parties maintain these positions then with the inquiry is expected to last for up to a year and it could be a year before there is a chance of breaking the political deadlock.

Mr Adams by his remarks appeared to open up some possibilities for manoeuvre where Ms Foster would lead her party’s negotiations but would allow a caretaker First Minister in her place until there was a preliminary report.

Mr Adams reminded reporters that Sinn Féin’s initial demand was for Ms Foster to stand aside was pending an interim report into RHI.

“The first position we put was that Arlene Foster should stand to one side until there was a preliminary report. We are now being told there is not going to be a preliminary report. Where all this comes from none of us knows - the inquiry has not set out its mode of operation and all of that,” he said.

“Our position is very, very straightforward: we will not be consenting to Arlene Foster being the First Minister until this issue is cleared up. As soon as it can be cleared,” he added.

“Arlene Foster has said on a number of occasions that she is innocent and we haven’t tried to make a judgment on that. So the inquiry may decide that it isn’t going to take these issues except on a 12-month or nine-month schedule. But it might decide that it is going to bring forward a preliminary report or it might decide that it is going to deal with these issues in modular form,” said Mr Adams.

He referred to how former DUP leader Peter Robinson previously stood aside at times of political crisis. “Let’s not be misrepresenting the absoluteness of our position. What was good enough for Peter Robinson is good enough for Arlene Foster,” said Mr Adams.

The Sinn Féin president at the press conference was accompanied by senior Sinn Féin figures such as its Northern leader Michelle O’Neill, vice-president Mary Lou McDonald, MEPs Martina Anderson and Matt Carthy, TD Pearse Doherty and MLA Gerry Kelly.

The fact that Sinn Féin won 27 seats compared to the DUP’s 28 demonstrated that this was an “historic” and in “many ways a watershed” election, he said.

“Clearly the unionist majority in the Assembly has been ended and the notion of a permanent or perpetual unionist majority has been demolished,” said Mr Adams.

Michelle O’Neill said she would be having conversations with the Northern Secretary James Brokenshire and the Minister for Foreign Affairs Charlie Flanagan over Saturday and Sunday and that she had “also made contact with the leaders of all the political parties to talk about next week and how we are going to conduct ourselves the time ahead”.

Ms O’Neill pointed out how there are three weeks to form a new Executive after which Northern Secretary Mr Brokenshire should be obliged to call fresh elections.

“While the task isn’t easy I think it is achievable if we work on it with the right attitude. On Monday morning I will lead our team into the Assembly. We are ready to deal with all the issues,” she said.