Luas operator Transdev has accused SIPTU members of systematically orchestrating toilet breaks as part of a work-to-rule, resulting in disruption and delays to services.
The accusation comes in a letter from Transdev Human Resources Manager David Horgan to SIPTU.
The letter warns that if SIPTU continues with the alleged industrial action involving toilet breaks known as Personal Needs Breaks as part of its current work-to-rule, Transdev will consider legal action to recover any financial penalties incurred as a direct consequence of the drivers' actions.
Transdev also warns that any employee delaying the tram service will be liable to disciplinary action up to and including dismissal.
SIPTU's assistant industrial organiser John Murphy told RTÉ that no official or unofficial action related to the toilet breaks was being taken in furtherance of the current industrial dispute.
He said he understood that toilets at Bridesglen at the end of the Green Line were unavailable for use, and as a result, drivers had had to take breaks at the Sandyford and Red Cow depots.
In the Transdev letter, the human resources manager describes the alleged policy of orchestrating toilet breaks as a direct and illegitimate escalation of industrial action, adding that this policy was not listed in the notice of industrial action.
He says that if the action continues, Transdev will classify it as unofficial industrial action and may have no option but to remove PNBs which impact on the tram service in their entirety.
Prior to taking four days of strike action in the last fortnight in their pay dispute, Luas staff belonging to SIPTU had commenced a work-to-rule.
In the letter, Transdev says their records clearly indicate what they call a "substantial and unprecedented increase" in the number of toilet breaks taken by tram drivers as recently as Wednesday, Saturday and yesterday.
It says this resulted in significant delays to the tram system, and serious disruption to the travelling public.
It says its records indicate that on Wednesday, 16 toilet breaks were taken, 26 were taken on Saturday, while 18 were taken yesterday.
It says that most of the 60 toilet breaks on those days led to requests for relief at Red Cow or Sandyford which the company provided.
However, the company notes that having examined the records since the inception of Luas, there has never been any day historically where that level of breaks was required.
It also notes that in the period from January 1 to February 5 this year, before the current work-to-rule began, a total of just 22 toilet breaks were taken.
Transdev claims this action is "clearly orchestrated" by SIPTU to bring pressure to bear on Transdev, resulting in delayed tram departures, tram regulation issues and an impact on the exact timing of members' breaks.
Transdev management and SIPTU are due to attend the Workplace Relations Commission on Wednesday in a bid to break the deadlock which led to a shutdown of the service for four days over the last fortnight.
Further industrial action is scheduled for next month - including St Patrick's Day.
The escalation of the row over the toilet breaks is likely to be viewed as unhelpful in the run-up to the WRC talks.
