More than one third of residential mortgage accounts in arrears were behind on their repayments for 720 days or more by the end of February, according to the Department of Finance.
There were 84,717 accounts in arrears at the end of February, according to the department's latest mortgage restructures data, which was down 3,101 (3.5%) on the previous month.
However 28,936 (34%) of those were behind on their repayments for more than 720 days, with a further 30,202 (35.6%) in arrears for 90 days or more.
Meanwhile the total number of accounts that had been restructured by the end of February stood at 106,402 – up just 127 (0.12%) on January.
The overall arrears figure has fallen almost 7.9% when compared to November 2014, however mortgages in arrears still represented 12.3% of all housing loans on the books of the countries six main lenders by the end of February.
Of the permanent restructuring deals agreed, 30% saw arrears being recapitalised while 23% involved a split mortgage.
Within the temporary restructuring deals, 52% saw borrowers move to interest-only repayments, while 14% involved a moratorium on repayments.
On the buy-to-let side, a total of 28,603 accounts were in arrears by the end of February – down 1.8% on the January figure.
Arrears cases represented 23.5% of all buy-to-let mortgages on the books of the country’s six main banks, with the vast majority of those (82.2%) in arrears of 90 days or more.
There was a 2% rise (373) in the number of accounts permanently restructured, which stood at just over 19,000 by the end of February.
Of these deals, 28% involved arrears recapitalisation, while a further 22% saw repayments fixed.