Permanent TSB has reported that in the first six months of 2012, 13.2% of its residential mortgages are more than 90 days in arrears.
That's an increase of almost 2% on the second half of 2011.
When houses bought as an investment are included the percentage of residential mortgage arrears rises to 14.1%, also an increase on the second half of 2011.
Figures from the bank also show a loss after tax of €566m for the first half of 2012.
The figure allows a provision for bad debts of €437m, an increase of €92m on the same period last year and largely due to losses on commercial property mortgages.
The operating loss from core activities was €21m a fall of €5m from the first six months of 2011.
Permanent TSB CEO Jeremy Masding said that the figures highlighted the challenge facing the bank and pledged to invest in certain areas such as finance and asset management in the bank as well as the branch closures outlined earlier this year.
The bank also notes a number of key developments. It says that it has submitted its restructuring plan to the EU, that the €4 billion recapitalisation of the group is complete as is the sale of Irish Life and associated business.
The accounts also note that the bank's standard variable rate has been cut, bringing it into line with other banks, corporate deposits have also grown by €1.3 billion to €3.6 billion.
The bank announced that as part of its restructuring earlier this year that up to 250 staff would leave the company and 16 branches would close or be merged.