Police are warning people to be vigilant after at least three cash machines were altered in Auckland and Hamilton.
The Auckland City Financial Crime Unit says the alterations, known as skimming, allows the skimmers to gain access to personal information, including secure PINs.
ATMs that were skimmed were in the Hamilton suburb of Dinsdale, and on Karangahape and Ponsonby roads in Auckland.
Detective Senior Sergeant Hywel Jones says the matter was brought to police attention when a customer reported a false fascia on one of the ATMs.
It's not clear how many customers have been affected, or how much money has been stolen.
Investigators say the three cases appear to be connected.