The dissident republican group, the 32-County Sovereignty Committee, will hold its first public meeting next week to try to build a campaign of opposition to the peace process. The attendance will be interpreted as a sign of whether the group is attracting support from republicans disillusioned with the Stormont talks.
The meeting will be held next Tuesday night in Dundalk Town Hall, and at least five others are planned, including one in Belfast. A group of republican activists formed the committee last month.
Its vice-chairwoman is Ms Bernadette Sands McKevitt, sister of the dead IRA hungerstriker Bobby Sands. The group believes the Stormont talks will inevitably lead to a partitionist settlement and has pledged to oppose anything falling short of Irish unity.
Tuesday's meeting will be addressed by several present and former Sinn Fein members, including a sitting party councillor in Tyrone, Mr Francie Mackey. Much of the discussion is likely to centre on the blueprint for the Stormont talks published by the British and Irish governments on Monday.
One organiser is Mr Rory Dougan, who was among 30 Sinn Fein members in Co Louth who resigned from the party in November. He said: "We have called this meeting to let people know what we stand for. We would welcome Fianna Fail supporters as much as members or former members of the republican movement opposed to an internal settlement in the North.
"The document produced by the governments validates our position. It is blatantly obvious that the Union is secure and, if anything, is being strengthened. The cards are finally on the table now. This is a crunch time for the leadership of the republican movement. Will they finally have the courage to tell their members where they are taking them?
"The deal on offer is a far cry from what the republican struggle was all about. People have been frightened to voice opposition, but I am confident that over the next few months that will change and many ordinary republicans will come to agree with our position."
Mr Dougan said four more meetings were planned for the Republic, and one for Belfast, and others would possibly be held in Tyrone and south Down. Ms Sands McKevitt said the group had recently set up new committees in Cork, Waterford, Wexford and Limerick.