11am: Luas staff have been accused of sparking a pay crisis in the public sector.
Founding President of the University of Limerick Doctor Ed Walsh said the drivers' demands had set a bad example for other workers.
He said: "They have inflamed the whole industrial relations situation in Ireland. Dublin Bus are now looking for pay parity with Luas; Irish Rail (workers) are making a 25% claim; gardaí are unhappy; the teachers are making a 30% claim for new entrants and local authority councillors are looking for a 39% increase, God bless them."
Update 8.40am: Siptu is warning that the Luas strike could turn into a lockout with workers expected to be put on protective notice today.
Dublin commuters could be facing a full strike after talks yesterday failed to bridge the gulf between Transdev and Siptu.
There have been eight days of strikes since February with a number of further days of action planned in the pay dispute.
Siptu organiser John Murphy said the actions of the company could lead to a lockout of workers.
"This is firmly at the company's door. The company are saying they will lay people off. There's a threat to deduct money from workers' wages, which is astounding in this day and age," he said.
"Basically, it's a lockout, without using the word lockout," he said.
Passenger representatives say it is now time for SIPTU to be realistic in the Luas pay row.
Rail Users Ireland (RUI) say the people who travel on Dublin's tram service have been completely forgotten about in the in the midst of the dispute.
An all-out strike now appears to be on the cards after Transdev and SIPTU failed to break the deadlock at last-ditch talks yesterday.
Workers are expected to be officially placed on protective notice today amid warnings that loses from sustained strikes may be recouped from staff.
Mark Gleeson of the RUI said at a time when construction of a Luas expansion is underway, the situation is becoming more and more stark.
"It's hard to understand. The expansion to the Luas is a good thing, and guarantees more jobs for drivers," he said.
"Passengers are being discommoded. Siptu needs to get realistic."