Sinn Fein leader Gerry Adams has said Northern Ireland's political institutions are in "serious difficulty".
peaking at the party's annual 'think-in' he said a "negative political axis" was seeking to undermine the Good Friday Agreement.
Mr Adams was speaking after comments made by Peter Robinson during an interview with the Belfast Telegraph this week.
The First Minister described Northern Ireland's current political state as "not fit for purpose".
The DUP leader had called for the removal of checks and balances in the original St Andrews Agreement, which his party concluded with Sinn Fein, the other major parties and the two governments in October 2006.
He said the safeguards - which ensured most parties a seat in government and allowed powers of veto and had made decision-making sluggish.
Deputy First Minister Mr McGuinness reacted with anger and suspicion.
"Let me say the assertion the institutions aren't fit for purpose isn't one I agree with," he said.
"The difficulty is those working the institutions have to be fit for purpose and have to have a commitment to equality, parity of esteem and recognising there are others in government with them."
Speaking in Termonfeckin in Co Louth on Thursday, Gerry Adams said:
"As everyone knows, the political process in the north is currently in serious difficulty. A negative political axis is currently seeking to undermine the Good Friday Agreement and turn back the clock on the progress of recent years.
"We now have the ludicrous position of unionist leaders, who repeatedly walked away from talks, asking for new talks."
"Unionist political leaders may hanker after a return to majority rule in the north but that is never, ever, going to happen. The Orange State is gone forever."
Mr Adams claimed the "British Government's interventions to date have merely encouraged unionist intransigence".
"Sinn Fein is open to negotiations and dialogue and we have been very clear that the Irish and British Governments and the US administration should be involved," he said.