ANZ is apologising after a major computer foul-up caused thousands of bank transactions from May to repeat last night.
Money previously debited from accounts was debited again, risking the tripping of overdraft limits.
This puts further pressure on ANZ, which is already on a PR offensive over the death of the National Bank brand.
ANZ spin doctor Stefan Herrick says a "payment processing glitch" involving a file being duplicated, causing "a couple of thousand" transactions from a date in May to occur again.
"This meant some customers of other banks incorrectly received a debit or a credit to their account.
"This was discovered quickly and we are reversing those transactions today.
"We'd like to apologise for the error and inconvenience caused."
Mr Herrick would not talk about compensation but says if the transactions sparked fees by tripping overdraft limits, customers should contact their bank and "their bank will address any of those issues with us".
Earlier this afternoon Plaster Options director Bruce Papp told NBR ONLINE two cheques previously presented from May 3, totalling $3500, came out of his account again last night in a repeat transaction.
"They've just grabbed $3500 out of our account and I haven't heard from anybody at the ANZ."
"I think ANZ, if they made a stuff up, they should start getting on with putting things right, maybe even contacting me."