Union officials have stepped in to try to help 200 Polish workers at the ESB's Moneypoint power station after the company they were employed by had its contract terminated.
The Technical, Engineering and Electrical Union (TEEU) said many of the workers had not been paid for up to six weeks.
They said they would be seeking to get the back pay handed to the men and see if any new sub-contractor brought in to complete the work would take the workers on.
The workers had been employed by polish company ZRE which was a sub contractor to Lentjes which yesterday said it was cancelling the sub-contract with immediate effect.
ESB said Lentjes had informed it of the decision and that it was taken because of issues over ZRE's compliance with Irish labour and employment law.
Dan Miller, assistant general secretary of the TEEU, said he would hold a meeting with the 200 workers on Monday and would be seeking to discuss the unpaid wages with both Lentjes and ESB.
He said the union would also be pressing to see if the workers could be employed by any new contractor brought in to finish the work.