Ervia's group of unions has referred the company's decision not to pay controversial bonuses awards to Irish Water workers, to the Labour Relations Commission.
Workers at the company insist they have earned the bonuses and are now entitled to receive them.
The issue of bonus payments at the new water utility has been politically sensitive since details of the performance related awards became public last year.
Details included the fact that some staff who are deemed to "need improvement" can still benefit from a pay award.
The controversy prompted Minister for the Environment Alan Kelly to say at the time that he did not want to see a "bonus culture" emerge at Irish Water.
RTÉ's This Week understands that unions and management at Irish Water's parent company Ervia will attend a conciliation conference at the LRC on 13 July, on the dispute.
The bonus payments were introduced as part of a new pay model at Ervia (then known as Bord Gais Éireann) in 2013.
Irish Water inherited the new pay model when it was established as a utility under Ervia two years ago.
No performance related awards have been paid out at Irish Water yet but they were due to be paid earlier this year to cover work done in 2014.
However, company management informed the unions that this would not go ahead.
Ervia has repeatedly defended the pay model saying that it had brought considerable savings when compared to the previous increment-based pay model at Bord Gais.
It also rejected descriptions of the performance awards as being comparable to a traditional 'bonus' and instead they have described it as a 'pay-at-risk' element of pay.
In a statement, Ervia confirmed that the group of unions had referred the dispute to the LRC in recent weeks and that a conciliation conference had been scheduled for 13 July.
Speaking on This Week, Adrian Kane of SIPTU said Irish Water workers were angry that they were not being paid their performance related awards - and that it appeared to them that the decision was made at board level without a clear or consistent rationale being given for the non-payment of the bonus awards.
He said the performance-related awards were a key element of the pay model negotiated between the unions and the company back in 2013.
