Black Africans are four times more likely to be out of work than white Irish-born citizens, it has emerged.
Researchers found the immigrant group suffered the lowest rate of employment and also faced seven times more discrimination both in the workplace and when looking for a job.
The labour force participation was just 60% for black Africans and 65% for Europeans who were not white in 2010, while it ranged from 72% to 80% for white Europeans and Asians, many who arrived on student visas and could legally work part-time.
Professor Philip O'Connell said the severe disadvantages suffered by black Africans may be due, in part, to the fact that many are regarded as refugees.
"People who enter the country as asylum seekers spend a considerable period of time excluded from the labour market, and in many respects excluded from participation in Irish society, under the direct provision system," said Prof O'Connell, director of the UCD Geary Institute.
"Long-term non-employment can have a scarring effect on subsequent employment prospects. If you are excluded from work for a long period of time, your skills deteriorate and it's very difficult to get a job again."
The findings, based on 2004 and 2010 surveys from the Central Statistics Office, were published by the Economic and Social Research Institute (ESRI) and Equality Authority.
Researchers said the number of non-Irish nationals in work more than doubled from 164,400 in 2004 to 341,500 at the end of 2007, at the peak of the boom, but as unemployment soared and the recession deepened, the gap between Irish and foreign nationals in work grew.
Black Africans were more likely to be employed in 2010 than six years earlier, which could be because of a change in legal status. However, they still recorded the highest unemployment rate (36%), while white people from the 'old' EU-13 member states had the lowest rate (9%), followed by Asians (12%). Irish nationals also held the majority of professional and managerial occupations.
Renee Dempsey, chief executive of the Equality Authority, said the report showed immigrants did not fare as well as Irish nationals in the Irish labour market. "Clearly there needs to be a renewed focus on promoting equality for immigrants and for minority ethnic groups in the labour market and throughout society," she added.