All Luas staff have been served with protective notice with immediate effect by Transdev, the operator of the Dublin light rail service.

In response, Siptu - which represents workers at the company - said it was now looking at a ballot for an all-out strike which would bring the light rail service to a halt indefinitely.

The company said in a letter to employees on Tuesday that if strikes continued beyond April 24th, it would reserve the right to seek to recover the costs of the dispute from staff engaging in industrial action after that point.

It also warned of pay deducations for staff who were not fully carrying out their contractual duties.

It said the employment of staff in all four grades at the company would be employed on a day-to-day basis until further notice.

In its letter to staff, Transdev said: “As much advance notice for such lay off or short time working will be given as is reasonably possible in the circumstances. However, given the nature of the industrial action it must be recognised that there will be occasions where any such notice will be extremely limited.”

Transdev said it was prepared to engage with the trade union Siptu “on the format of any lay off/short time working”.

Management at the light rail operator also said it would “no longer accept part performance of contracts by staff and it was putting its drivers and traffic supervisors on notice of its intention “to apply an appropriate financial reduction and will invite their and Siptu’s response to that proposals”.

Siptu accused the company of escalating the dispute by breaking off all talks and threatening the livelihoods of its members .

“This move makes a negotiated settlement to this dispute even more remote,” it said.

The company said that traffic supervisors were engaging in an on-going work-to-rule - in addition to the various strikes that have taken place - while drivers were scheduled to recommence a work-to-rule on April 17th.

“During the work-to-rule you will be aware that there are a significant number of duties that are not being performed that form an integral part of the contract of employment or the company/union agreement. To date the company has paid staff in full on these days as we had hoped that this dispute would long since have been resolved”, the company said in the letter to its employees.

Transdev also said it considered intermittent industrial action as an element of “part performance” and that it reserved the right to require all staff to fully perform their contractual duties.

“If a staff member on request refuses to carry out an instruction to perform any duties that are an integral part of their contract of employment or the company/union agreement, they will be deemed to have removed themselves from the payroll pending a resolution of the dispute.

The company offered staff a lower pay increase than that drawn up in talks at the Workplace Relations Commission last month and which was rejected overwhelmingly by staff.

It said this revised proposal would remain in place until April 17th.

Siptu disvisional organiser Owen Reidy said: “Siptu members are engaged in a lawful trade dispute and are fully compliant with both their collective agreements with the company and the Industrial Relations Act 1990. If this was not the case the company would have sought a court injunction before now. It has not done this as it has no grounds to do so.”

“In the letter the company proposes that members should consider an offer to resolve the dispute that is inferior to a proposal from the Workplace Relations Commission that was rejected by 99 percent of staff. Unfortunately, it is quite clear the company is in no mood to resolve the dispute. Siptu will support its members against their employer’s actions and is now considering a ballot for an all-out strike.

Siptu said its members were now calling on the other stakeholders in the dispute to clearly condemn the company’s actions. It urged the company to make itself available for further talks.

“Only through dialogue can we reach a settlement to this dispute that all parties can accept.”

Transdev managing director Gerry Madden said on Tuesday evening that night the company would do everything reasonable to ensure it remained as the operator of the Luas system..

He said the company had a responsibility to its customers but that Siptu was making demands that were unreasonable.

He said in an RTE interview that Transdev did not want a full stoppage of the service and further strikes could not be tolerated. However he said the company could not magic up money it did not have.

Strike action is currently planned for the following dates: Saturday, April 23rd; Sunday, April 24th; Thursday, April 28th; Wednesday, May 4th; Friday, May 13th; Friday, May 20th; Thursday, May 26th (Four hour work stoppage from 3pm–7pm); and Friday, May 27th.