Transport Minister Shane Ross is facing renewed attacks on his handling of the pay dispute at Dublin Bus as it enters its latest two day strike.
Union leaders at Siptu branded his remarks that he was not a "sugar daddy" ridiculous and incredible. They called on him to accept his responsibilities to bus users.
The war of words deepened with services shutting down at 9pm and not back on the roads until Sunday morning, with no Nitelink buses running on Friday or Saturday for people socialising in the city.
Siptu organiser Owen Reidy said company bosses and the Department of Transport have shown a complete lack of interest in resolving the dispute.
"It is no longer sustainable for the Minister for Transport to sit back and say this dispute has nothing to do with him when he is responsible for public transport," he said.
"His line about not being 'a sugar daddy' 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."
Siptu claimed Dublin Bus management has made no effort to engage with unions.
Dublin Bus said it will have lost €6m by the end of the latest walkout, leaving it in debt for the year.
And with another 13 strike days planned the company is set to lose €15m.
Dublin Bus apologised to the 400,000 bus users left with limited transport options over the next 48 hours and pleaded with unions to call off the action.
"Dublin Bus has come through an extremely tough financial period in recent years due to the recession and has only just reached a stable financial footing," a spokeswoman said.
"We have a responsibility to our employees and to the taxpayer to manage our finances to safeguard the economic and financial stability of the company.
"We remain willing and open to engage with the trade unions and urge them to return to talks as provided for in the Labour Court recommendation, so that we can work together to move forward and find a resolution to the current dispute."
Further strike days are planned for Saturday October 1 - the All-Ireland football final replay, then Wednesday 5, Friday 7, Monday 10, Wednesday 12, Friday 14, Tuesday 18, Wednesday 19, Monday 24, Wednesday 26 and Saturday 29.
A protest march is planned by Dublin Bus union members through the capital to the Dáil next Tuesday as TDs return to Leinster House.
General secretary of the National Bus and Rail Union Dermot O'Leary turned his criticism to civil servants in the Department of Transport who he accused of being answerable to noone.
He also accused them of trying to dismantle Bus Eireann as the Dublin Bus pay dispute threatens to spread.