The Irish Republican Socialist Party, the political wing of the INLA, has condemned the peace agreement as anti-republican and a "charter for further conflict".
"What we are witnessing is the realisation of the nightmare scenario that republican socialists flagged up over two years ago," a member of the party's ardchomhairle, Mr Gerry Burns, said.
Mr Burns was speaking yesterday at the party's annual Easter commemoration at the republican socialist plot in Milltown Cemetery, west Belfast.
He called for a "massive No vote" in referendums in the North and on proposed changes to Articles 2 and 3 of the Republic's Constitution.
"Failure to do so will leave a section of our nation, the nationalists living in the north-east of Ireland, as stateless citizens living in their own country. It will also prolong British occupation."
He also called on republicans within the provisional movement to reject the peace document at Sinn Fein's Ardfheis in Dublin this weekend.
"They must demonstrate that they will not be railroaded into accepting proposals that are an assault on republican ideals," he said.
A British intention to withdraw from the North and the establishment of an Irish socialist state were needed to achieve a political solution.
While the British military occupation of Ireland continued, the party reserved the right "at any time to engage the British forces in Ireland and those who target the nationalist working class", he said.
Through the "politics and agitation" of the IRSP and the "cutting edge" of Irish National Liberation Army volunteers, they could move forward together, "one creed, one class and hasten the day when our aim is achieved."