Several ANZ customers have been billed by Netflix as someone attempted to guess bank account numbers in the streaming service's free trial sign up.
ANZ confirmed a small number of customers were affected in New Zealand over the weekend but the majority of the transactions were automatically reversed.
"We are monitoring customer accounts for any suspicious activity.
"A small number of customers made touch with us and we replaced their card," a spokeswoman said.
No customers would be out of pocket.