The National Transport Authority has described the decision made by Luas workers to reject pay proposals and proceed with strikes on Easter Sunday and Easter Monday as a "blow to the centenary events" that are taking place in the capital this weekend.
Earlier, Luas employees overwhelmingly rejected pay proposals which included pay increases of up to 18% over a period less than three years.
Planned strike action on Easter Sunday and Easter Monday will affect thousands of people planning on visiting the 1916 Centenary commemorations in the city centre.
NTA Chief Executive Anne Graham said there should be enough extra capacity on buses and trains to cater for the hundreds of thousands expected to attend the events.
She also urged people to use public transport to travel into the festivities, in particular on Sunday when extra road closures will be in operation due to tight security
After four days of strike action in February, and the threat of further action on St Patrick's Day and Easter, Luas operator Transdev and SIPTU hammered out proposals at the Workplace Relations Commission in a bid to resolve the dispute.
However, from early on sources among the workforce warned that there would be resistance - as many felt the deal was not enough.
Some of their reservations concern longer individual shifts and lower starting pay levels for new employees.
Of the 167 drivers who voted, only two voted in favour of the WRC proposals.
SIPTU Divisional Organiser Owen Reidy said: "It seems quite clear that there is a complete breakdown in the relationship and trust between the driver grade and management at the company.”
He said some drivers rejected the proposals because "drivers did not want to accept a new pay scale that leaves new entrants on lower pay than current staff."
He added: "Drivers are of the view that the productivity sought in the proposal was disproportionate and vague in the case of the Luas extension", referencing the Luas cross city expansion due to begin services next year.
It is clear that the workers believe that they can secure a better deal despite the fact that the WRC told them that this was the best that could be negotiated.
Management at Transdev expressed their "shock and disappointment" at the rejection of the proposals.
Managing Director Gerry Madden said the proposal was at the "very outer limits of what we could afford" and in "accordance with the terms of the WRC document that proposal is now withdrawn".
He added: "We will not be issuing any knee jerk response. This decision has serious implications for the company and our staff and we will reflect over the weekend and issue a considered response".
This ballot result means that the strikes on Easter Sunday and Monday will go ahead.
In a statement, Minister for Transport, Tourism and Sport Paschal Donohoe said he was surprised and disappointed at the decision by Luas employees' to reject pay proposals.
"The terms of the WRC proposal involved a generous package of pay increases for the workers from their employer - far in excess of what many other private or public sector employers could possibly afford for their staff at this time.
"So it is difficult to understand the Luas workers' rejection," he said.