The Irish Congress of Trade Unions has called for tough new regulation to ensure that employers cannot exploit migrant workers.
The ICTU General Secretary, David Begg, accused employers of a culture of impunity highlighted by recent cases involving foreign workers in Irish Ferries and Gama Construction.
Mr Begg said it would be in Ireland's best interests to ensure that employees could not be abused, as many sectors - including hospitality, health and horticulture - were now dependent on migrant workers.
Meanwhile, the Tánaiste, Mary Harney, has rejected accusations that she did not act swiftly enough on complaints about the Turkish-owned construction company, Gama, when she was Minister for Enterprise and Employment.
The company is currently in a dispute with its Turkish employees over wages for work on Irish sites.
Ms Harney said any complaints were followed up and that the trade unions representing workers were consulted by officials in her former department.
She denied accusations that she had ever shown any company favouritism or that she had gone to Turkey to lobby Gama to come to Ireland.
Ms Harney said she would not stand over any group of workers being discriminated against, and that she would roundly condemn it.
