A five-hour demonstration by employees of the Turkish construction firm, Gama, at Tynagh in Co Galway ended shortly after 9pm tonight.
SIPTU union officials met local management at the site of a power plant that Gama is building in Tynagh.
Afterwards SIPTU Branch Secretary, Adrian Kane, said they were very disappointed with the outcome of their talks.
Workers are protesting against low wage rates at the company, and are also demanding detailed information about accounts which were opened in their names in a Dutch bank.
The workers claim the accounts could contain as much as €30 million.
Earlier, the Minister for Enterprise, Trade & Employment, Micheál Martin, said he has received further complaints regarding the treatment of the workers at the firm.
Mr Martin has asked officials in his department to seek an urgent meeting with the managing director of Gama Construction Ireland to clarify the situation.
Gama Construction is currently under investigation by the Department of Enterprise, Trade and Employment following claims of below minimum-wage payments and wage fraud.
Around 200 Gama employees, who were joined by Socialist Party TD Joe Higgins, staged a march to Leinster House in Dublin yesterday.