Banks are providing a current account "jungle" and hurting the most vulnerable customers, a watchdog says.
The banks are accused of providing a "jungle" of current accounts
The National Consumer Council called on regulators to force banks to give better information about interest charges on statements.
Some bank charges could harm low-income account holders who exceed their overdraft limit by pushing them further into debt, the council said.
But banks have said UK customers can avoid all fees by staying in credit.
Customers can pay up to £39 if they exceed their overdraft limit.
The council said the hidden costs of "free banking" should be investigated and, to get a better deal for the least well-off in society, the Office of Fair Trading should include basic bank accounts in its investigations.
NCC chief executive Ed Mayo said: "Navigating through the current account jungle can be a real challenge."
People are often reluctant to switch accounts as they feel the process is too complicated, or they are worried about standing order and direct debits not being paid, he said.
"Those on low incomes or with limited banking experience are most likely to be adversely affected.
"It is about time banks stopped pulling the wool over people's eyes and started behaving more responsibly."
Brian Capon of the British Bankers' Association said customers in the UK can avoid fees altogether by staying in credit, whereas in most other countries people have to pay even for everyday banking transactions.
He said: "The fees are clearly published by the banks on websites, in branches and through telephone helplines.
"If you do go overdrawn and it's a genuine mistake, do speak to your bank and if it's a one-off they are likely to refund the charge."