However, CIMB did not name the service provider.

In an email to FMT the bank said the problem involved “a limited number of customers that undertook international to local transfers”.

The processing error led to transfers made to customers being accidentally processed twice.

“This resulted in affected customers receiving duplicate credits into their accounts, i.e. a duplicate transaction which effectively doubled the total amount of funds received by the customer,” CIMB said.

The bank reiterated that the duplicate transfers were from the bank’s funds, not from the sender or the receiving party.

In such cases, it said a “hold and earmark” was placed on the duplicate transaction to recover the mistaken payments. The accounts were not frozen, the bank said, in response to complaints by customers last week. “Customers are still able to utilise balance funds in excess of the earmarked amount placed on hold,” it said.

CIMB said it had taken note of instructions by Bank Negara Malaysia to ensure fair treatment of those involved.

The bank said it has been in touch with affected customers for a fair and managed resolution, with clear evidence of double credits and how they can repay the sum through flexible schemes.