Some 56 per cent of sub-prime mortgages are considered to be more than 90 days in arrears, compared to the national average of 17 per cent.
The information was contained in a Dáil reply to Fianna Fáil finance spokesman Michael McGrath by Minister for Finance Michael Noonan.
Mr McGrath had asked the Minister to clarify the number of residential mortgages in Ireland that are classified as sub-prime, the total value of sub-prime mortgages outstanding and the rate of arrears on these mortgages.
"There was a total of €3.354 billion in outstanding primary dwelling (PDH) debt and a further €0.132 billion in outstanding in buy to let BTL mortgage debt. Of that outstanding debt, mortgage accounts amounting to €1.885 billion (PDH) and €0.050 billion (BTL) respectively were in arrears of over 90 days," Mr Noonan said.