The Government is finding it difficult to recruit labour inspectors, the Dáil was told.
As Labour leader Pat Rabbitte claimed there were more dog wardens than inspectors in the State, Taoiseach Bertie Ahern said that there is "difficulty in getting people to take up this kind of job".
An increase to 31 in the number of labour inspectors has been approved, and applicants had been interviewed for the positions but "dealing with this end of the labour market is not seen as a very attractive profession even though the remuneration is quite good," he said.
The issue of treatment of migrant workers was raised in the wake of the rescue of 13 east European workers off Skerries, Co Dublin, after being stranded on an uninhabited island while picking periwinkles.
Mr Rabbitte said the case was "the latest, but most extreme example of the casual, regular, everyday exploitation of immigrant workers - in particular poorly paid workers".
Mr Ahern condemned the Skerries case and the actions "of an employer of some sort".
He had been given a name and investigations would establish whether the employer had a licence for periwinkle production. If so, he was subject to 25 Acts and was being investigated in five areas.
Highlighting other cases, Mr Rabbitte pointed to an ongoing dispute at Doyle Concrete in Rathangan, Co Kildare, "where workers have been dis-employed to allow for the employment of cheap labour".
Mr Rabbitte said there were "horrific cases" of people working in domestic service, who are "prisoners in the homes of this country's nouveaux riche" and excluded from the Employment Equality Act.
The number of inspections carried out had gone from 8,372 in 2002 to 5,160 last year and only four new inspectors had been appointed.
That was less than one per 100,000 people. "There is less than one per county. Every county has a dog warden, but not every county has a labour inspector," Mr Rabbitte said.
Mr Ahern said there were fewer inspections last year because personnel were taken from other work to investigate Gama Construction.
The Government took a "very dim view" of some employers trying to improve their margins by getting rid of Irish workers and replacing them with workers on lower earnings.
When Socialist TD Joe Higgins said it was going on wholesale in the meat industry, Mr Ahern said "it is a well known fact that it is nearly impossible to get an Irish person to work in the meat industry".
