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.
ANZ also confirmed no accounts in Australia were affected by the incident.
A spokeswoman for Netflix said "a small number of ANZ consumers had a nominal, temporary verification hold placed against their credit cards by someone attempting to guess ANZ card numbers in the Netflix free trial sign-up process".
The activity had been identified and blocked and most of the temporary verifications were "already reversed, and we are cancelling any invalid Netflix accounts which were created".