Bank of Ireland has increased interest rates it charges on some personal loans and overdrafts.
"These rate changes are driven by the ongoing costs associated with the provision of these products," the lender said in a statement.
Sinn Féin spokesman on finance Arthur Morgan said Bank of Ireland's move would hit low and middle income earners hardest and highlighted the need to form a state bank.
"This will push these people who are already struggling over the edge. Businesses are also suffering in the credit crunch and when they can get them, many are reliant on overdrafts," he said.
"In return for the recapitalisation of these banks, ordinary taxpayers have received a further harsh blow to their personal finances.
"We need nationalisation to make sure that individuals and businesses have access to credit at fair rates and we need to make sure the State continues to have its own bank well into the future."
Last month, Permanent TSB came under fire when it announced it was raising its standard variable interest rate on mortgages from February 1st. The 0.5 per cent hike was the second time in a year that the lender had upped its rates.
At the time, the bank blamed the “challenging business environment” for its decision.
Additional reporting - Bloomberg