Hopes of resolving the Luas industrial dispute have received a setback after the Workplace Relations Commission called off negotiations due to take place next week.

Earlier this week, Luas operator Transdev and SIPTU attended the WRC separately and afterwards, Director General Kieran Mulvey invited the two sides to intensive talks starting on Monday.

However, this afternoon sources at the WRC said because of alleged ongoing unofficial industrial action involving excessive toilet breaks, there is no basis for successful negotiations at this point.

It is understood Transdev contacted the WRC to say it was not in a position to attend talks while the alleged unofficial action continues and reiterated that position in a letter to SIPTU.

It has also told SIPTU that as the alleged action is unofficial and unlawful, both the union and individual workers are not protected by immunities under industrial relations law, and may be pursued for any financial losses to the company as a result of the action.

The dispute over pay has already shut the service down for four days in the last two weeks.

Further disruption and delays has been caused by a work to rule which commenced on 6 February - and by a significant rise in the incidence of drivers taking toilet breaks.

In its letter to SIPTU, Transdev notes that the increased incidence of toilet breaks (known as Personal Needs Breaks) since the dispute began has continued, even since the WRC asked that it should cease.

The company describes this as unofficial action, which ia clearly unlawful and intended to disrupt the public and damage the company.

They say they were given to understand the SIPTU officials were going to intervene in the matter.

They say that normally employees who engage in this type of behaviour would be removed from the payroll.

However, they say that they do not want to be forced to penalise people who they claim are being misled.

The company says that from Sunday morning, it is setting a limit of three toilet breaks in any 24-hour period, saying it gives more than ample scope for genuine cases over the course of the working day.

They warn that they will be making "proportionate" payroll adjustments to reflect this unofficial action.

They also tell SIPTU that as the unofficial action is unlawful, drivers are not covered by immunities under the Industrial Relations Acts and could leave themselves personally and their union liable for any financial losses or penalties that the company incurs because of service disruption.

Transdev has also warned that it will not enter negotiations in any forum until the incidence of toilet breaks returns to normal pre-dispute levels.

SIPTU Divisional Organiser Owen Reidy said SIPTU has responded to Transdev saying it has at all times advised members that they may only take official industrial action.

He said that the union had enquired as to whether the toilet breaks had been orchestrated as part of unofficial action, but had been told they were not.

He said that if it were true, SIPTU would neither condone nor support it.