Two nights of strife for NAB payments

Were last night's plans successful, National Australia Bank will sometime this morning have corrected its mishandled processing of salary, Centrelink and business payments on Wednesday night.

Most likely NAB will have made a second sweep of empty accounts for direct debits last night, so doubling complaints from customers and merchants about an error put down to a "corrupted file".

Two nights of processing problems could be a symptom of deeper defects in NAB's payment processing arrangements, though the bank does not accept this view.

"What's happened today is unfortunate,'' chief executive Cameron Clyne told reporters, after a lunch in Sydney.

"We are very sorry for the inconvenience to customers. We are processing payments now and will work as quickly as possible to fix it.

"Unfortunately, with a large organisation these things happen from time to time."