CIÉ unions meet on Friday to decide whether to deliver the "summer of discontent" anticipated by the Minister for Transport, Mr Brennan. A consensus has yet to emerge, however, on how best to respond to the public transport reforms planned by the Minister.
An action committee set up to consider the issue two weeks ago will report to the unions at Friday's meeting.
It is understood a smaller group will attend than was present at the unions' last meeting a fortnight ago, when five hours of talks ended without agreement on how to proceed.
Union leaders are believed to be fearful of the potential impact on public opinion of all-out industrial action.
But there is a considerable push for strike action aimed at forcing Mr Brennan to back down on his plans to dismantle CIÉ and allow private operators to compete in the Dublin bus market.
Unions are particularly opposed to his plan to have 25 per cent of the Dublin bus market opened to competition by next January. Sources say they would be prepared to discuss allowing private operators on new routes in an expanding market, but they want existing Dublin Bus services ring-fenced.
A public meeting is to be held in Dublin tonight as part of a campaign to secure support for the unions' stance.
The meeting, at the Teachers' Club in Parnell Square, is to be addressed by a bus driver from England about the impact of privatisation on transport services there.
Mr Dave Manningham, a shop steward with the T&GWU, says privatisation in Britain resulted in dramatic increases in fares and a decline in passenger numbers of as much as 40 per cent in some major cities.
Mr Brennan, however, is known to favour a route franchising system similar to that operated in London, where passenger numbers have increased by 30 per cent over the past 10 years. He has said that while his plans might lead to a "summer of discontent", they would result in a more efficient service to the public.
Other speakers at tonight's meeting, which is being organised by a group of Dublin Bus workers, will include the assistant general secretary of the National Bus and Rail Union, Mr Michael Faherty, and CIÉ worker-director Mr Bill McCamley of SIPTU.