The DUP's suggestion that Sinn Féin be "disbanded" has been described as "farcical and unrealistic" by south Belfast councillor Mr Alex Maskey.
At the launch of the DUP's 36-page analysis of why the Belfast Agreement has failed, party leader the Rev Ian Paisley said there could be no talks with Sinn Féin under the current circumstances.
"Sinn Féin is a terrorists party," the North Antrim MP insisted. They should have no part nor be in any negotiations. We are democrats. The only way forward for this country is on a firm, undiluted and real democratic basis.
"The IRA has to be utterly disbanded. Sinn Fein, as it stands, has to be disbanded. If a new party was formed to represent republicans in a democratic way then that would be the way forward for them."
But Sinn Fein's Mr Alex Maskey said: "The DUP's demand for the disbandment of Sinn Féin is as farcical and unrealistic and unrealisable as their demand for a renegotiation of the Good Friday Agreement."
"The reality is that Sinn Féin is supported by the majority of the nationalist community in the North.
"The reality is that there will be no re-negotiation of the Good Friday Agreement. Some of Dr Paisley's party colleagues know and privately accept this.
"Today's comments are less about Sinn Féin and more about containing those in the DUP who accept that they will have to come to terms with and deal with Sinn Fein."
Mr Paisley also claimed the Belfast Agreement was dead and needed to be replaced after an election.
He said their document outlined how his party had been right to oppose the Belfast Agreement when it was created in 1998.
Fresh Assembly elections were needed in Northern Ireland, he claimed, to enable parties to negotiate a new settlement. However he accused the British government of running scared of a poll and of sticking blindly to the Agreement.
"We are not going to have anything to do with this old Agreement," he said. "The old Agreement is dead and buried."
In its document the DUP insisted the current Agreement could not command the support in the unionist community which would make it function.
The party insisted that its failings were not simply of concern to unionists but to anybody who wanted accountable democracy in Northern Ireland.
The Belfast Agreement needed to be replaced, the document argued, by a settlement which was "clear in its terms" and "accepted by unionists and nationalists alike".
"It is clear that the Belfast Agreement is a process towards a united Ireland. Instead Northern Ireland needs a constitutional settlement which is secure and lasting."
SDLP leader Mr Mark Durkan also insisted the Agreement would not be renegotiated.
After meeting Northern Ireland Secretary Paul Murphy at Stormont, Mr Durkan said he had told the British government that the public needed to know the Agreement remained the "working template for all the parties".
PA