Thousands of commuters are facing further travel disruption this evening, as a work stoppage by drivers at Dublin Bus continues.
Work stoppages are planned for today and tomorrow, as well as 13 more days across this month and next.
No Dublin Bus routes, sightseeing tours or Airlink services will operate, while Nitelink buses will not run either tonight or on Saturday.
Minister for Transport Shane Ross has repeatedly declined to intervene in the dispute, saying he is not prepared to open the "state chequebook".
Union members are seeking a 15% pay rise over the next three years, as well as a payment in lieu of an agreed 6% increase that was deferred in 2009.
Dublin Bus insists it can only afford the 8.25% increase recommended by the Labour Court.
The company estimates that industrial action has cost it more than €4 million to date, with this week's stoppages costing an additional €2 million, leaving it in a loss-making position by the end of 2016.
In a letter to employees on Wednesday, CEO Ray Coyne urged all grades to re-engage in talks.
"Unlike the impact of the economic crisis which was outside our control, resolution to the current situation is within our control at this point," he said.
"This ongoing industrial action is undermining all our past efforts and has the potential to return the company to a post 2010 financial crisis.
"This would naturally require actions to restore the company to a sound financial standing.
"Returning to such a scenario is totally unnecessary and is at this point wholly avoidable."
'Sugar daddy'
However, Dermot O’Leary of the NBRU said unions were not to blame for ongoing disturbances faced by passengers.
"The trade union side are committed to engaging without preconditions. It's a matter for Dublin Bus as to whether it will reciprocate."
SIPTU has also called on Minister Ross to "play a constructive role" in finding a resolution.
Organiser Owen Reidy said yesterday: "Since the industrial action began there has been absolutely no engagement by Dublin Bus management with their workers’ representatives.
"It is no longer sustainable for [Shane Ross] to sit back and say this dispute has nothing to do with him when he is responsible for public transport.
"His line about not being 'a sugar daddy' [while speaking to the Dáil transport committee] is both ridiculous and incredible.
"He claims that he is merely a shareholder in Dublin Bus when in reality the Department of Transport has responsibility for deciding upon the strategic direction of public transport and the amount of state funding that will be provided to deliver services."
Former general secretary of the Civil Public and Services Union Blair Horan told Newstalk Drive that he doesn't think there is an immediate resolution in sight.
"Industrial relations and disputes are always very difficult to predict, I have to say," he explained. "But I certainly wouldn't think that there's an immediate resolution of this dispute in prospect - and it could go on for a bit."
