Political representatives of the INLA, a small republican armed group, has said its understanding with the 26-County government is in trouble following its refusal to allow former leader Dessie O'Hare home leave over the holiday period.
The controversial figure known as the Border Fox, sought temporary release this year to spend Christmas with his wife and family.
The refusal of Michael McDowell, the Dublin government's justice minister, to allow O'Hare leave has provoked a furious response from Irish Republican Socialist party (IRSP), which is allied to the INLA.
The group followed the IRA in declaring a ceasefire ahead of the 1998 Good Friday Agreement.
Eddie McGarrigle, a member of the IRSP Ard Chomhairle, said the organisation was taking O'Hare's case as a litmus test of the Dublin government's good faith.
McGarrigle said: ``Let's be clear about this, a good sense of cynicism now exists among the membership of this movement who see our leadership and prisoners being treated with contempt by the Free State government, elements of which are shamelessly using Dessie as a hostage.
``This puts them in serious default of their responsibilities and obligations.
He also warned that the government should be ``concerned about the ceasefire in the medium term''.
Since he was affiliated with a paramilitary group on ceasefire, O'Hare was deemed eligible for early release under the terms of the Good Friday agreement. The Dublin government has, however, refused to implement the recommendation in the case of O'Hare, who they allege is psychotic and unstable.
The Dublin government also refused to release a group of IRA prisoners held at Castlereagh jail in County Roscommon over the death of Garda Jerry McCabe. They have provided no reason for their continued incarceration.
``The Irish government should now be concerned about the INLA ceasefire in the medium term, because if the people who are pushing peace-building efforts and initiatives walk away from the process who is going to take their place? I am considering doing that at the moment,'' McGarrigle said.
``Northern nationalists and republicans watch and do not cry foul as some of the most vicious pro-British loyalists, who have literally cut people into small pieces for no other reason other than religion, walk the streets.
``This is because they recognise this as part of the process that may one day lead to peace on this island. They see it as worth the risk if peace is the prize.
``Risks must be taken and courage must be shown if the process is to work and it must work for everyone not just a few or those deemed to be acceptable to the PDs. The cases of Dessie O'Hare and those imprisoned for the killing of a Garda during the late war encapsulate this. If it's over it's over, you can't cherry pick who you let out and who you keep in.''