The move comes after the release of figures showing that 6,472 Romanians were issued with personal public service (PPS) numbers since the country joined the EU on 1 January 2007, while in the same period just 22 work permits were handed out.

Though they are members of the EU since January, Romanians and Bulgarians require a work permit to work in Ireland. But in what Siptu described as a loophole, if you are deemed self-employed you do not need a work permit.

Siptu said that a large portion of these Romanians, who cannot get social welfare payments for two years, are being exploited by builders who hire them as selfemployed contractors on rates well below the legal minimum for the construction sector.

A spokesman for the Romanian embassy admitted that initially there was some confusion among Romanians and many thought they could work without a permit.

"But many have since returned home after they found they needed a permit.

But they are not working here illegally, " said the spokesman.

Brendan O'Brien of Siptu accused the Revenue Commissioners of "turning a blind eye" to the practice.

"It is extremely lax about checking whether these contracts are genuine, " he said.

A Revenue spokesman said that new legislative powers introduced last month which allows Revenue to share employment information with Enterprise, Trade, and Employment and the newly established National Employment Rights Authority, will allow a more focused investigation in the construction sector. It would not necessarliy concentrate on the Romanian community, he said.