Luas services faced disruption this evening because 11 of the company's 100 drivers reported sick today.
A spokesperson for the Luas operator, Connex, said that as yet they have no evidence to link the drivers' absence with a one man unofficial picket mounted today by an employee dismissed from the company.
SIPTU's union recognition agreement with Connex includes a no strike clause that prevents the staff from taking industrial action.
The Connex spokesperson said that a number of trained managers drove trams today to plug gaps in the schedule arising from the drivers' absence.
However, Connex anticipated that some services would be cancelled later in the evening.
The spokesperson said that the picketing employee had not exhausted the internal appeals process, and said that Connex had been in touch with SIPTU in a bid to resolve the dispute.
