Using your hand to shield your PIN while using an ATM may no longer be enough to protect against skimmers, who are using increasingly sophisticated equipment to deceive customers, police say.
The warning comes as detectives hunt for members of an organised crime gang with links to eastern Europe who are suspected of targeting more than 40 ATMs across Sydney and skimming more than $100,000 from unsuspecting customers.
Detectives have released CCTV footage of three men, shown at ATMs on Market Street in Sydney and in Campsie, who are wanted for questioning following a sharp rise in skimming incidents across the city since mid-January.
The suburbs where skimming devices have been found include Artarmon, Avalon, Balmain, Bexley, Bondi Junction, Burwood, Campsie, Caringbah, Chatswood, Clovelly, Dee Why, Double Bay, Dural, Gordon, Hurstville, Haymarket, Kingsford, Mona Vale, Mosman, Neutral Bay, Parramatta, Ramsgate, Rockdale, Seven Hills, Strathfield, St Ives and the Sydney CBD.
Police said the skimming devices used by the group were capable of copying card details, while a tiny video camera recorded people entering their personal identification numbers (PINs).
A copy of the card was then created, allowing the group to access the account holders' funds.
Detective Inspector Matt Craft said the cameras being used by the gang were more sophisticated than what had previously been used in ATM scams.
While previous cameras only picked up footage from the top of the keypad, now they could pick up different angles.
Inspector Craft urged ATM customers to be more vigilant with covering their hands while they typed in their PINs.
"Use your wallet, your purse, a newspaper - something else so that it's covered virtually [all over] and not just the top," he said.
"That's the best way to combat this particular type of crime."
Last month, two men - one from Hungary and one from Romania - were arrested after allegedly tampering with an ATM on Market Street in Sydney. Both men have been charged and are before the courts.
Detectives are now searching for three more men, including two who were captured on CCTV also at an ATM on Market Street in Sydney on March 28.
Police described one man captured in the vision as being of eastern European appearance and aged in his 20s or early 30s. He was wearing a navy blue, long-sleeved shirt.
A second man captured in the vision was described as being of eastern European appearance and aged in his 20s or early 30s. He was wearing a navy blue polo shirt and black baseball cap.
Detectives have also released a CCTV image of another man who was captured at an ATM on Beamish Street in Campsie on March 21.
Police described that man as being of eastern European appearance and aged in his late 30s or 40s. He was wearing a light long-sleeved shirt, dark pants and shoes and a dark baseball cap.
Detective Superintendent Arthur Katsogiannis, the commander of the Fraud and Cybercrime Squad, said the criminal group was highly organised and sophisticated and had already bagged more than $100,000 through the scam.
"This type of crime is the choice of criminals in the 21st century," he said.
"With the advent of technology, advancing at an exponential rate, this will be more and more common.
"Our investigation, which has been strongly supported by a number of banks, suggests that the spike in ATM skimming incidents can be attributed to an organised syndicate targeting ATMs in suburbs right across Sydney.
"While we have arrested some members of the group, we know there are still a number out there, so cardholders need to exercise caution when using ATMs."
Detective Superintendent Katsogiannis encouraged anyone who recognised the men to call Crime Stoppers on 1800 333 000 or to use the Crime Stoppers online reporting page.