Two Canadian have been arrested today in relation to skimming devices being attached to Christchurch ATMs.
The devices are capable of recording customers' card details and enables them to be used fraudulently, said Detective Sergeant Joanne Parks.
"It is a timely reminder for members of the public to be aware when using ATMs. Anyone noticing anything added to an ATM or anything unusual about an ATM should report it to the bank immediately."
Anyone who thinks that they have had unauthorised use of their cards need to check their accounts and contact their banks to close their accounts as soon as possible.
"You can protect yourself by keeping an eye on your card at all times and make a note of where and when you use it, and remember to cover your PIN while completing a transaction."
Anyone who believes they are a victim of crime, in person or online should report the matter to their local police.
Both of the men, aged 28 and 39, have been charged with accessing a computer for a dishonest purpose.
They will appear in court on Monday. More charges are likely to follow.