The SDLP could be poised to leave the North's Executive and take a place on the opposition benches.
The party's leader Colum Eastwood and West Belfast MLA Alex Attwood met with Stormont's leaders earlier but left after just half an hour expressing disappointment.
Mr Eastwood claimed the SDLP had entered the post-election negotiations with the determination to find a Programme for Government they could sign up to, but added: "It is clear that we are not able to achieve that and we now have to go and speak to our party."
A meeting of senior SDLP figures is taking place at Stormont's Parliament Buildings with an official announcement on the party's predicted Executive exit expected later.
In a hard hitting statement, issued jointly, First Minister Arlene Foster and Deputy First Martin McGuinness slammed the SDLP accusing the party of dishonesty.
"For the SDLP to now claim they do not agree with the Programme for Government process is dishonest given that they were part of developing it," the ministers said.
"The new PfG has not been plucked out of thin air. It has involved extensive consultation with political parties in the Executive, including the SDLP, dating back to last December.
"Either the SDLP had no intention of joining the new Executive and are playing to the gallery and the media.
"Or, they failed to grasp the new approach to government and are not up for the challenges ahead.
"Or, in an act of desperation inspired by their poor election result, they are now preparing to slavishly follow the Ulster Unionist Party out of government."
Mrs Foster and Mr McGuinness pledged to move forward.
"We are committed to putting together the best possible PfG that will create more and better jobs and investment in our health service, our schools and support for the most vulnerable in society," they added.
Meanwhile the Alliance Party still has to confirm whether it will take on the contentious Justice Ministry after walking out of Stormont Castle after just a few minutes.
The decision on whether to accept the DUP/Sinn Féin offer to again take on a post it has filled since 2010 has become crucial to the viability of the next executive.
If the cross-community party declines, Stormont will be facing another crisis, just weeks after the Assembly election, as neither the DUP or Sinn Féin are likely to allow the other to assume the politically sensitive portfolio.
That mutual veto has been overcome in recent years by the willingness of Alliance to take the job.
Alliance Party leader David Ford has made clear his party will only fulfil the role again if it achieves progress on five key policy issues - building an integrated society; funding of services, not division; "cleaning up" of politics; investment in jobs, skills and economy; and ending all forms of paramilitarism.
Green Party MLA Stephen Agnew and Independent unionist Claire Sugden have also been summoned to Stormont Castle amid speculation they could be offered the justice portfolio.
Mr Agnew described his discussion with the First and Deputy First Ministers as "worthwhile and constructive" but said more progress was needed.
He said: "We raised our key issues including Green New deal, integrated education and investment in early years provision. The traditional parties have failed to address these issues to date.
"However we would need more progress on our issues before we could recommend going into government to our party members."