Luas drivers have served notice of further industrial action for four extra days next month.
The drivers said they will strike again on 2 and 3 April, and 23 and 24 April.
Strikes are already scheduled for St Patrick's Day, Easter Sunday and Easter Monday.
SIPTU district divisional organiser Owen Reidy said the drivers had been left with no alternative.
Managing Director of Transdev Gerry Madden said: "The public will have no tram service for St Patrick's Day, no tram service for Easter Weekend and now no tram service for two weekends in April.
"The public, Luas customers and business are the real losers here.
"Transdev is in talks tomorrow in the Workplace Relations Commission with three out of the four grades in the company. Luas traffic supervisors, revenue protection officers and supervisors.
"All of these grades are willing to enter talks with the company in the WRC," Mr Madden said.
"Transdev is willing to talk with the driver grade in the WRC but have stated that those talks will only be meaningful if the pay claim is modified to a reasonable point.
"I am disappointed with the notice served today and the total disregard being shown to the public," he added.