Momentum Support says it's referring the industrial action by its cleaning staff at University Hospital Waterford to the Labour Court.
However, Unite says it's not been informed of the arrangement of a Labour Court hearing and will have to consult its members.
It's after talks between the company and Unite trade union broke down last night.
The dispute is over changes to staff's working conditions without consultation.
In a statement, Momentum says it's made every effort to avoid industrial action by Unite and to engage in the process.
It says it put forward a number of proposals last night to help resolve the issues but these were rejected.
Momentum is appealing to Unite to postpone the industrial action while the matter is before the Labour Court.
