Ulster Bank has reported an overall operating loss of £219m sterling (€250m) for the three months to the end of September. This compares with a loss of £176m the same time last year.
The bank, which is owned by Royal Bank of Scotland, said its impairment losses rose from £269m (€307m) in the second quarter of the year to £327m (€373m) in the third.
Ulster Bank said the economic climate in Ireland remains tough, with impairments remaining at a high level.
But it said it has a ''strong underlying franchise'' and its operating profits - before impairment charges - came to £108m (€123m) for the three-month period.
The bank said its customer numbers rose by 3% overall in the third quarter of 2011 compared to the same time last year. It saw a 3% increase in consumer banking and a 2% increase in SME and business customers.
Royal Bank of Scotland returns to profit
Royal Bank of Scotland today reported pre-tax profits of £2 billion sterling in the three months to September 30, compared with a loss of £1.6 billion the same time last year.
The British government owns 83% of the group following a huge state bail-out that was triggered by the 2008 global financial crisis.
The bank said it expected difficult market conditions in the fourth quarter, with banks around the world hit by Europe's debt crisis, and the part-nationalised lender added it had taken more writedowns on its Greek exposure.
RBS followed the likes of Barclays and Morgan Stanley in benefiting from a debt accounting gain, which boosted its earnings by £2.36 billion and helped offset lower profits at its GBM investment banking division.
RBS added, however, that it had taken a further impairment loss of £142m on its exposure to Greece during the third quarter.
"RBS's third quarter results show the improved strength and resilience we have built up since 2008," Chief Executive Stephen Hester said. "They also highlight the external pressures facing banks, and economies more broadly, which are making the road to recovery longer and bumpier than hoped for," he added.
