Work permit regulations will be changed to prevent "unscrupulous" Irish employers and employment agencies from exploiting immigrant workers, according to the Tanaiste, Ms Harney. An "aggressive campaign" is also under way by the labour inspectorate, targeting creches, the agriculture sector and, in particular, mushroom and meat plants, as well as hotel and catering. "Priority is being given to target areas where a large number of work permits have been issued and where there have been complaints against particular employers," the Tanaiste added.

The inspectorate was systematically investigating recent reports alleging abuse affecting foreign nursing and hotel and catering staff. Implicated employers and employment agencies are being pursued with a view to prosecution and a number of prosecutions are pending.

Administrative co-operation with regulatory authorities in other countries is being considered to control "extortionate" fee-charging by employment agencies which facilitate the placement of foreign workers in Ireland.

Ms Harney said the regulation changes include requiring prospective employees to sign work permit applications to confirm they are familiar with and accept the terms of the job on offer.

Fine Gael's enterprise spokesman, Mr Charles Flanagan, said there was systematic exploitation of eastern European workers, particularly in the agribusiness sector and the outdoor pursuits area.

He said that many workers coming to Ireland "are promised jobs to which they are indentured as a result of the personal nature of the work permit and many of them work overtime without pay and have to work for weeks with no days off".