ANZ has taken a one-off charge of A$27 million after uncovering shortcomings in the methodology used to accrue loyalty points for some co-branded cards.
ANZ says that since 1999, points for the Qantas ANZ Business One Card and bonus points for international expenditure on the Qantas ANZ Card have been under-accrued.
The shortcomings were only identified during a review of the bank's card business in the wake of recent reforms to interchange fees mandated by the Reserve Bank of Australia.
ANZ says it has moved to make management changes in the cards issuing area and increased financial controls within the business.
Reporting a stable earnings outlook for the year ahead, ANZ CEO John McFarlane says: "Despite the problem in our credit card issuing business, recent overall momentum has been good, expenses are being managed well, and international credit issues appear containable."