As many as 200,000 Commonwealth Bank customers across Australia found themselves short of money on Tuesday after an on-line glitch mistakenly duplicated withdrawals from their accounts.
The bank said the problem occurred in processing overnight.
It hoped to rectify it later on Tuesday but admitted it could take until Wednesday morning.
CBA spokesman Steven Batten said money was taken out of some accounts following bill payments and withdrawals over the weekend.
“Overnight, there were some transactions that have been duplicated as a result of a processing problems,” Batten said.
“We’re still trying to confirm the cause and we understand around 200,000 customers have been impacted.”
He said customers who have incurred fees because of the error will not be out of pocket.
“If they have been charged any fees such as overdrawn fees they can contact us and we will refund them,” he said.
One man told Fairfax Radio that he pulled into a petrol station at 1am (AEDT) on Tuesday and went to pay with his credit card but was told there was no money in his account when there was supposed to be over $5000.
Batten said customers affected by the processing error and in need of cash should visit one of their branches.