The Democratic Unionist Party has predicted there will be a renegotiation of the Belfast Agreement regardless of the contents of the two governments' salvage package.
The DUP deputy leader, Mr Peter Robinson, claimed the package's proposals would be unable to attract the support of the wider unionist community, thus rendering it "meaningless".
"There will be a renegotiation of the [Belfast] agreement and it doesn't matter what they stick together on this occasion. It won't be able to command the support of the community and therefore will collapse. Ultimately, there will have to be an agreement which will have the support of both sections of our community, and not just the nationalists," he added.
Mr Robinson yesterday met the Northern Ireland Human Rights Commission to press for the release of the package to his party. The governments intend to release the document only to the pro-agreement parties, a move which the DUP is prepared to challenge in court, according to Mr Robinson.
He also questioned remarks made by Ulster Unionist leader Mr David Trimble over the weekend that there would have to be a "substantial review" of the agreement if the IRA failed to move on disarmament.
"I seem to recall David Trimble told us you couldn't have a renegotiation of the agreement. That was the position he adopted during the election and expressly in television programmes he made it clear that my suggestion that we could have a renegotiation of the agreement was something that could simply not happen.
"It appears that like his resignation [as First Minister] was for electoral purposes, the reality is that we were right once again," Mr Robinson added.
He said even another IRA statement promising disarmament would be "meaningless" as unionists needed to see proof that arms were completely and verifiably put beyond use.
The UUP chairman, Mr James Cooper, yesterday called on his party's members to speak with a "unified" voice on the disarmament issue.
"If the outcome of this phase of talks does not produce actual disarmament, then it is critical that Ulster Unionists speak with a unified voice. We must hold our nerve and ensure that the focus of media attention rests on the paramilitaries and their representatives who have reneged on their obligations to disarm and disband their illegal organisations."
Meanwhile, the Sinn Fein president, Mr Gerry Adams, has reaffirmed his party's long-term commitment to the peace process but rejected any speculation regarding a renegotiation of the Belfast Agreement.
"I will say very briefly that there can be no renegotiation of the Good Friday agreement. The Good Friday agreement is as good as it gets for everyone and we would be better using our energies as Sinn Fein are doing, trying to ensure that the Good Friday agreement is implemented."
Mr Adams called on the two governments not only to present the package to the pro-agreement parties tomorrow, as widely expected, but to also put it in the wider public domain to allay people's anxieties about possible secret deals.