The National Transport Authority has agreed to defer the tender process for 10% of Bus Éireann and Dublin Bus routes to allow for further talks on the controversial privatisation proposals.
The initial pre-qualification phase of the tender was due to get under way from 1 December.
However, after four hours of talks, NTA Chief Executive Gerry Murphy confirmed that they have agreed to "pause" the process until the middle of January to allow for further engagement.
SIPTU Divisional Organiser Owen Reidy said the union would be seeking a meeting with Minister for Transport Tourism and Sport Paschal Donohoe to discuss the issue.
NBRU General Secretary Dermot O'Leary said the opening up of routes to the private sector remained a red line issue for unions, and they would continue to oppose it.
The talks are being facilitated by Labour Relations Commission Director of Conciliation Kevin Foley.
Unions at Bus Éireann and Dublin Bus today described the NTA's proposals to privatise 10% of bus routes as a flawed ideological plan.
Mr O'Leary said he believed the plan would trigger a race to the bottom in pay and conditions for workers.
He said it could also result in the loss of 440 jobs and said the current proposals to protect staff transferring to private operators were not good enough.
If the NTA was determined to drive ahead with its proposals, he said the NBRU would have no option but to consult with members on what was essentially the axing of 440 jobs.
He also claimed that Bus Éireann and Dublin Bus had said the proposals could cost the companies €20m in legacy costs for certain staff who could not transfer to the new operators.
Asked whether their dispute was with the bus companies, the NTA or the Government, Mr Reidy said it was ultimately with the NTA through the Government.
He asked whether anyone thought there would be a better transport system by giving 10% of the market to new operators.
It would be a ham-fisted part-privatisation similar to the waste industry, he said.
He warned that they could then see more "Greyhound" situations, and that would be unacceptable.
There was no way that workers were going to pay the price for what he described as a foolish ideological plan, he said.
Mr Murphy earlier rejected the criticisms of the privatisation proposals, describing them as measured and appropriate.
He disputed claims of a race to the bottom in pay and conditions, or of redundancies.
Staff transferring to new operators would carry on their jobs, he said.
He noted that the bus companies would be retaining 90% of the market, and were permitted to tender for the 10% of routes that were being opened to the private sector.
He also pointed out that the Luas is operated by a private company, where workers are unionised.
