British bank HSBC has issued an apology to customers who were not allowed to withdraw large amounts of cash from branches in Britain.

Customers had told a British radio station, British Broadcasting Corp's (BBC) Radio 4, that they were prevented from taking money out of their accounts because they could not provide evidence of what they wanted the cash for.

Radio 4 reported on Saturday that some HSBC customers were stopped from withdrawing amounts ranging from 5,000 pounds (S$10,543) to 10,000 pounds in cash. They were told that they had to show proof of what the money was being used for.

The bank apologised on Sunday, according to a report by the New York Times.

HSBC said that the requests for information were part of a policy change that had been implemented in November, in line with efforts to comply with anti-money laundering regulations. The rules require banks to report suspicious behavior, such as withdrawing large amount of cash.

"It is not mandatory for customers to provide documentary evidence for large cash withdrawals, and on its own, failure to show evidence is not a reason to refuse a withdrawal," HSBC said in a statement quoted in the New York Times report.

"We apologise to any customer who has been given incorrect information and inconvenienced."

A BBC report said HSBC had not informed customers of the policy change but added that the bank has changed its guidance to staff.