Fears about the possibility of an all-out LUAS strike are mounting, as both sides stick their positions.
Pay talks between SIPTU and Luas operator Transdev broke down at the WRC last night.
SIPTU says it's still available for talks, but is considering balloting members for an indefinite stoppage.
The union says it has made "substantial" concessions and it will now back an all out strike if workers vote for one.
Pay talks between the sides broke down at the Workplace Relations Commission (WRC) last night, despite workers almost halving their salary demands of 53%.
Trade union SIPTU says it is now considering balloting its members for all-out strike action, which could begin in five weeks time.
If nothing changes, strikes will go ahead on St Patrick's Day and over the Easter Bank Holiday weekend, with further possible action yet to be announced.
Gerry Madden of Transdev says "to be fair to SIPTU" the worker's demands have moved from "off the planet to now just off the scale."
Transport Minister Paschal Donohoe told Newstalk Lunchtime be getting involved at this stage.
Industry correspondent with the Irish Times, Martin Wall, told the Pat Kenny Show here on Newstalk the outcome of this dispute is being watched carefully by other transport workers.
Owen Reidy is a divisional organiser with SIPTU. He told Newstalk Breakfast earlier that workers could be asked to vote on all-out action in the next week or so.
"A ballot might happen in the next week or so, but it takes some time to complete".
"Then you have to get sanction, and you have to serve 21 days notice - at the earliest you would be looking at five weeks...that would be an indefinite action".
Meanwhile, the company that runs the Luas wants SIPTU to ballot their members again in the dispute.
Managing director of Transdev Gerry Madden says he is not convinced drivers still want to strike.
"We're not convinced from some of the conversations we are having with people locally that there is still a significant appetite for that".
"What we are saying is that every time there is a further strike, whatever day it happens - St Patrick's Day, whatever - it doesn't enhance my ability to give them a better pay deal. Quite the opposite, so therefore it is not what we would suggest is the right way forward".
"We want SIPTU and Liberty Hall to start getting involved more locally to try and get people understanding the consequences of such action", he added.