SIPTU has disputed the findings of an ESRI study on the effects of the arrival of people from the 10 EU accession countries.
The study found there was no evidence that Irish workers had been displaced from jobs by the arrival of people from these countries.
The study was carried out by the ESRI and researchers in Sweden. It discovered that people who come from the 10 accession countries who could not get work generally left Ireland.
Ireland's move to open its borders to people from that ten new accession states had caused concerns that the move could result in so-called welfare tourists, where people come here to enjoy better entitlements.
But today's report says those concerns have been proved groundless. 90% of the people who come here are in the workforce and most of the rest are dependants like children. The people who come here and do not find work generally leave.
183,000 people from the accession states have taken PPS numbers since May 2004, which entitles them to benefits. But the report says that this has had little effect on unemployment.
In a statement, SIPTU said the study's claim that there was no evidence that wage rates were being undermined was based on 'seriously flawed data'.
Head of research Manus O'Riordan questioned the CSO earnings data on which the study was based, saying the figures for the construction industry did not include the earnings of new employees in the industry who are being employed by sub-contractors.
