Allied Irish Banks has recorded its worst pre-tax losses of just over two billion euro for the first half of the year, it has been revealed.
The figure compares with 872 million euro for the same period in 2009, according to the bank's half-yearly results.
AIB, one of the six banks guaranteed by the State, said the six months from January were particularly difficult for the bank and its customers.
"A significant level of credit losses was experienced in the period in addition to the loss on transfer of the first tranche of loans to the National Asset Management Agency (Nama)," it said in a statement.
Managing director Colm Doherty warned that homeowners would face further pain as the bank, 18.6% of which is owned by the taxpayer, could follow Permanent TSB and Bank of Ireland in raising mortgage interest rates.
The half-yearly results also showed that losses for AIB Bank Republic of Ireland totalled 2.67 billion euro while the loss on transfer of the first tranche of loans to Nama was 963 million euro.
Bailed-out Bank of Ireland announced on Tuesday that almost 58,000 homeowners are to be hit with a hike in interest rates for the second time this year. The lender revealed that its standard variable mortgage rate will jump to 3.49% next Tuesday.
Permanent TSB, one of the country's biggest mortgage lenders, said last week that its standard variable customers would be hit with a 0.5% hike from August 3.