The European Consumer Centre is advising people travelling to eastern Europe to spend cash instead of using debit cards.
It says it has received numerous complaints from Irish consumers who have had their cards skimmed when buying items in restaurants and nightclubs.
One Irish man had €9,000 unknowingly deducted from his account.
Martina Nee of the European Consumer Centre in Dublin, said that cash is generally a safer option.
"We would advise people maybe to bring enough cash for the night, consider leaving the card at home," she said.
"If you bring your card, make sure you keep it in sight at all times and watch the amount on the screen, especially if it's in another currency.
"And if you suspect fraudulent transactions, then contact the police straight away."