Luas operator Transdev says it will cut drivers' pay by 10 per cent from this Friday if their work-to-rule continues.

The company claims the reduction reflects the costs being incurred as a result of the action.

Transdev says its written to SIPTU urging it to call off Thursday's strike.

The company says it's still open to talks "once a credible basis for negotiations exists".

The country's public transport system could be facing more unrest, after unions at Irish Rail announced ballots for industrial action.

SIPTU says it has referred its pay claim for all grades at Iarnrod Eireann to the Workplace Relations Commission.

The NBRU says it's holding an immediate ballot of its members and is accusing the company of refusing to deal with its pay claims.

Irish rail says the union's been involved in a series of walk-outs, unofficial actions and refusals to engage with the company.