Consumers are being "ripped off" by Northern Ireland's four largest banks, a leading watchdog has said.
Which? said the NI banks paid "paltry" interest
Which? - formerly the Consumers' Association - has lodged a complaint with the government over the way the personal banking market operates.
It says local consumers are being badly treated by the big four local banks.
In some cases, they are charged over 21 times more than customers in the rest of the UK.
However, the association said at this stage there was little consumers could do other than switch banks.
It presented its third "super-complaint" to the Office of Fair Trading (OFT) on Monday.
It will have 90 days to decide what action it will take.
The complaint is directed at the Bank of Ireland, First Trust, Northern Bank and Ulster Bank.
Phil Evans, principal policy adviser for
Which?, said: "Bank customers in Northern Ireland are being ripped off.
"The big four in Northern Ireland are all offering similarly inferior products, leaving their customers with little choice, indeed a choice between who will rip them off the least."
Which? said the banks paid "paltry" interest for accounts in credit -
They also charged up to 43p each time a customer used a cash machine, sometimes even when they were not overdrawn.
"Northern Irish customers are paying too much," said Which?
Its research showed a "staggering" difference between the cost of running overdrafts with one of the Northern Ireland banks in comparison
to one of its "best buys".
Someone with a £500 authorised overdraft for two weeks per month could
pay £11 a year with a lender, compared to £236 with one of the Northern Ireland "big four", said Which?
General Consumer Council chairman Steve Costello said in its judgment, the Northern Ireland market "plainly does not work for consumers".
"The banks must do the honourable thing by putting their house in order and
removing these excessive and unfair charges," he said.
"The OFT has the duty to investigate this in detail and answer questions
about the market's effectiveness once and for all."
He encouraged people to shop around for a better deal.