Three out of four refugee claim rejections were endorsed on appeal by the independent refugee appeals body in its first full year in operation last year.
The Refugee Appeals Tribunal upheld 75 per cent of negative decisions by the Refugee Applications Commissioner, with Nigerian nationals accounting for one in five of all appellants.
The tribunal's annual report for last year shows that the average time to process an appeal was six months or less. The tribunal has almost cleared a backlog of 1,806 appeals.
The number of appeals received last year rose to 4,192, compared to 3,702 in 2000. Nigerians accounted for almost 25 per cent of appellants, with 18 per cent of appeals from Romanians. Other significant nationalities included Algerians, Moldovans, Czechs and Kosovars.
Nigerian and Romanian nationals account for the largest number of refugee applicants.
People claiming the right to live permanently in Ireland as refugees must show that they have a well-founded fear of persecution on grounds including race, religion or nationality.