Talks between Irish Water management and unions at the Labour Relations Commission have been adjourned.
The two sides were meeting in a bid to defuse a row over pay increases withheld by the company.
When Irish Water was set up, parent company Ervia introduced a new pay structure there and in Bord Gáis, with annual increments abolished.
Instead, a portion of a worker's salary was withheld and had to be earned as a performance-related award.
The company estimated that the new system saved €34 million a year between the two companies.
However, there was public controversy when the system was revealed, as many viewed the performance related award as bonuses.
The company then announced that in light of the public outrage, it was withholding the PRAs.
SIPTU, IMPACT and the TEEU attended the LRC in a bid to force the company to pay the outstanding amounts.
SIPTU Sector Organiser Adrian Kane said the LRC would be reconvening the parties, though a date has not yet been set.
He declined to comment on whether progress had been made at today's talks.
Irish Water declined to say how much money had been withheld from workers in unpaid PRAs - though sources confirmed that the assessment of individual staff to calculate the size of the PRA due to each one has been carried out.
Arriving for the talks today, SIPTU Organiser Adrian Kane said he estimated that between 3% and 6% of total pay due to workers had been withheld.