The company said drivers working to rule and a signaling problem caused delays to the Red Line
Luas services are back to normal in Dublin tonight, following delays earlier this evening.
In a tweet, the company apologised to passengers, saying a work to rule and a signaling problem had caused issues.
It is understood the action affected Red Line services in particular.
Luas services running normally . Work to rule and a signal issue caused earlier probs- apologies— Luas (@Luas) February 20, 2016
It followed a 48-hour strike on the service this week, which affected 90,000 passengers.
Talks aimed at averting further strike action by Luas drivers are expected to take place next Wednesday.
The Workplace Relations Commission has invited the Luas operator Transdev and driver unions to discussions.
Further industrial action is planned for March 8th and again on St Patrick's Day.
The dispute is over pay demands, with drivers arguing for increases of up to 54% over five years.
Transdev says it cannot afford to pay the proposed rates, but SIPTU has indicated there is room for negotiation.