A threat of industrial action affecting bus and rail transport was lifted yesterday, at least for a further week.
Union representatives decided to accept an invitation to enter new talks with the Minister for Transport, Mr Brennan, on his plans for CIÉ.
They warned last night, however, that industrial action remained imminent unless Mr Brennan could assure them meaningful negotiations would take place.
Unions are opposed to Mr Brennan's plans to dismantle CIÉ and allow increased competition from private operators.
The two sides are expected to meet next week. If a formula is not found to begin a new talks process, the unions will reconvene to draw up a timetable for industrial action.
The CIÉ unions had intended to agree such a timetable at a meeting yesterday in Dublin. An 11th-hour intervention by the Minister, however, changed the agenda.
In a letter to the Irish Congress of Trade Unions general secretary, Mr David Begg, the Minister said he was committed to resolving the impasse between them and invited the unions to meet him or his Department.
An existing talks process broke down this week following interviews given by Mr Brennan in which he restated his commitment to competition and the break-up of CIÉ.
In a statement following their meeting, the unions said they were "reluctantly" accepting the Minister's invitation, "given the past history of similar invitations".
Unions claim Mr Brennan has continually undermined negotiations by making public statements on his intentions. Both sides, their statement said, needed to find a new process that would have integrity and would address members' concerns.
Mr Liam Tobin of the NBRU said the unions had not deferred their planned campaign of action. A timetable had not been announced because some union representatives had to consult their committees, he said.
He was not optimistic of a successful outcome to next week's meeting, he said.
Mr Michael Halpenny of SIPTU said the onus was on Mr Brennan to prove he was committed to finding a resolution.
In his letter to Mr Begg, Mr Brennan said it was usual for Ministers to be interviewed about policy objectives. "I do believe that both sides should be able to hold their public position, as indeed both sides have, without that leading to a breakdown in discussions." He said most of his planned reforms had been agreed by the social partners, including unions, in the public transport partnership forum. The differences were "mainly to do with scale and timing".
Aer Rianta unions meet today to consider discussions they have held with the Department of Transport over Mr Brennan's plans to break up that company. They may decide to reinstigate industrial action, which was deferred to allow those talks to take place.