Researchers have found that black African immigrants are four times more likely to be unemployed than white Irish adults.

They also report the highest levels of discrimination of all the Republic's ethnic minorities.

The findings were published by the ESRI and the Equality Authority, which has called for a renewed focus on promoting equality for immigrants and minority ethnic groups.

Responses from 17,000 people interviewed by the Central Statistics Office a little over two years ago reveal that black Africans are seven times more likely than white Irish people to report experiencing discrimination both when looking for work and in the workplace.

They are also over four times more likely to be unemployed than the white Irish and, together with whites from the EU's new member states, are less likely than the white Irish to be earning more than €38,000 net per year.

Only white people from the UK and the 13 older EU member-states escape what the authors call "significant rates" of workplace discrimination.

Members of ethnic minorities from inside the EU are four times more likely than white Irish people to report experiencing bias when job hunting.

This reported bias became more pronounced for all categories of people immigrating during the recession.

The authors call for a planned public policy to integrate immigrants, particularly refugees who have been excluded from work for a long time.

One of the authors said that being visibly different in Ireland "hurts".

Phillip O'Connell, who is also the director of the Geary Institute in UCD, told RTÉ's Morning Ireland that the discrimination against immigrants in the work place is a permanent feature of Irish society.

He said CSO figures show the levels of discrimination did not change between 2004 and 2010.

However, he said recent arrivals are finding it harder to settle into the labour market and are experiencing higher levels of discrimination.

Mr O'Connell said in most countries, immigrants in the labour market experience higher rates of unemployment.

He said in Ireland two groups stand out: black Africans and EU citizens of black or Asian ethnicity.

Mr O'Connell said what both of those have in common is that they are visibly different.

He said: "Being visibly different in Ireland does hurt, in terms of your labour market prospects and you are more likely to experience discrimination.

"But Black Africans are much, much higher than anybody else who is visibly different.

"We looked into the data to try to figure out what's going on there. And one of the things we found was that most of the black Africans who are in our survey were actually there since the early 2000s.

"Now, then most of them would have come in as asylum seekers. And I think what we are seeing is the long run effects of an asylum system which consigns people to a direct provision system so that they are cut off from society and that doesn't allow them to work."