The Luas drivers have announced more strikes for April
Luas drivers are to stage two further 48-hour strikes next month.
The drivers say they will strike again on the April 2, 3, 23 and 24.
Strikes are already scheduled for St Patrick's Day, Easter Sunday and Monday.
Talks at the Workplace Relations Commission aimed at averting further strikes broke down on Monday.
Drivers are seeking pay hikes of 30% over five years, they had previously asked for increases of up to 53%.
Siptu divisional organiser Owen Reidy says that tram drivers have been left with no other choice but to strike.
Mr Reidy said: "We were in talks on Monday and the employer broke down the talks with the drivers and said quite clearly in the WRC to their officials 'we are no longer going to negotiate with the drivers'.
"I've said it for some time myself, the only place this can be resolved is around the talks table, but you cannot talk to empty chairs.
"If the employer is refusing to engage with their own employees, with the drivers, what else are the drivers to do?"
