IRA units in the North have been told by their leadership that the ceasefire is "temporary", hinting that the organisation may still revert to its campaign of violence rather than face a potential internal split.
While Sinn Fein sources have insisted there is no serious split in the Provisional Republican movement - encompassing Sinn Fein and the IRA - there is increasing speculation that the dissident elements may be considering a leadership challenge.
Garda sources say the worst scenario would be if the level of internal dissent rose to a level where the IRA leadership had to expel the dissidents or return to a campaign of violence to unite the organisation.
It is now accepted that the IRA called off its last ceasefire largely to prevent a split, a development which, by tradition in republicanism, is almost always followed by feuding.
It is understood the dissidents are considering putting forward a spokeswoman with a considerable republican background, to give voice to their objections to the current direction of republican leadership policy.
Senior Garda sources appear to be uncertain of the level of dissent within the IRA. They are monitoring a number of key IRA figures living in the Republic to see which way they will move. One of these figures is said to be the IRA's director of operations.
There is understood to be particular concern along the Border area between Louth and south Donegal about dissident activity.
The concern is understood to have led the RUC Special Branch to issue a warning to divisional commanders in the force to ensure their officers are prepared for possible attacks.
There is said to be solid support for the ceasefire among republicans in Donegal and Derry and in Belfast. But there is uncertainty about the position being adopted by republicans in the mid-Ulster area where the local IRA units in east Tyrone, north Armagh and south Derry are known to be among the most hard-line elements of the republican movement.
According to senior Garda sources there is no sign yet of the dissidents transferring their loyalty to the splinter republican group, Republican Sinn Fein or its military wing, the Continuity IRA.
However, there is concern among gardai that the Continuity IRA group is receiving some explosives from dissident Provisional IRA figures and has also imported at least 10 rifles and sub-machineguns from the United States.
According to republican sources in New York, a former Provisional IRA gunrunner has switched allegiance to the Continuity group and has succeeded in sending a number of Mac-10 automatic assault rifles and Uzi submachineguns through the post to the Continuity IRA in the Republic.