A threat of public transport strikes has been averted, for the time being, following talks yesterday between unions and the Minister for Transport, Mr Brennan.
But while union leaders described the three-hour meeting as "positive", Mr Brennan said he remained committed to his plan to dismantle CIÉ and open the Dublin bus market to competition.
"I think it's better to hit it hard and fast, and try to get some agreement. A process like this could take a long time but I'm determined it won't."
Unions are particularly opposed to Mr Brennan's plan to have 25 per cent of the capital's bus market opened to competition by next January.
Following yesterday's meeting, Mr Liam Tobin of the National Bus and Railworkers' Union said the Minister had told them this plan was "not to be considered a fait accompli".
Discussions with Department of Transport officials would take place up to the end of March, and it had been agreed that no changes affecting CIÉ would take place in the meantime. There would be no need for disruption to services while the talks continued, given that unions were "back into the negotiating process".
Mr Noel Dowling of SIPTU said agreement was not guaranteed "but at least we've got the window of opportunity we were looking for to put our views clearly".
Mr Brennan said the meeting had been "very frank and very tough".
He had acknowledged the unions' "very strong objections" to his proposals "but, at the same time, I am firmly committed to the principle of opening up the markets and I hope that over the next seven weeks we can make substantial progress on that."
He had explained to the unions that he envisaged opening 25 per cent of the Dublin bus market to competition by January, and that legislation to that effect was planned.
Asked whether he had conceded this was not a "fait accompli", he said: "Well, it's self evident that it's not a fait accompli because it's not enacted."
He added, however, that he would take on board the unions' views on the future of public transport before "final decisions" were taken.
"I'm firmly committed to the idea of opening the market in Dublin but, of course, there's room to talk about mechanisms and percentages and things like that," Mr Brennan said.
It was up to both sides to convince the other of the merit of their positions, he added.