Officials from the National Bus and Railworkers Union (NBRU) are due to meet later today to discuss the possibility of reinstating their campaign of action against the proposed break-up of CIÉ.
Yesterday, the NBRU accused Transport Minister Seamus Brennan of a "shameless act of treachery" for telling the media that he would press ahead with the proposed break-up even though talks with the unions about the matter were still ongoing.
Liam Tobin, the general secretary of the union, said his members had now lost all faith in Mr Brennan.
"We were involved in a discussion forum with the department and the Minister for Transport and those discussions were ongoing when the minister decided to go to the press and make these announcements, which betrayed the trust of those meetings," he said.