Under the scam, Romanians arriving in Ireland were provided with a false address, usually a hostel, as well as other documents necessary to secure a PPS number from the Department of Social and Family Affairs.

The Romanians were charged up to Euro400 each for this service by their fellow countrymen, even though no fee is charged to secure a PPS number.

Social Affairs minister, S�amus Brennan, recently told the D�il that his department became suspicious in late January after thousands of Romanians applied for PPS numbers following their accession to the EU on 1 January last.

"A number of Romanian citizens have been interviewed by officers of the department, and further specific action will be taken in these cases where possible and where warranted, " Brennan said.

A department spokeswoman said it would also no longer accept a letter from a hostel as proof of permanent residence, expect in exceptional circumstances. All applications for PPS numbers will be subject to closer scrutiny, she added.

The department is also "concerned" as to how so many Romanians are managing in Ireland, even though they cannot work without a permit or draw any social welfare benefits for two years.

In the first two months after Romania joined the European Union, 5,291 Romanians have been issued with PPS numbers By contrast, just 213 were issued to Bulgarian nationals, who joined the EU on the same day.