GMC Civil and Mechanical Engineering staff at White's Cross called off a strike last week to engage in talks with the company.
The company which works on behalf of Gas Network's Ireland say they are disappointed that discussions at the WRC concluded without agreement and say they made numerous concessions throughout the process.
GMC says the matter has now been referred to the Labour Court.
Speaking to RedFM News Adrian Kane from SIPTU says the company are "not serious" about finding a resolution to the dispute:
" It has been one of the most frustrating processes I have ever been involved in. We essentially had an agreement with the company at the end of May. We balloted on it and accepted it. It provided for modest pay increases and some productivity increases. The company walked away from that. We spent the last three days and talks and I've come to the view that this company doesn't have the capability or the skill set to negotiate a settlement"
