Aberdeenshire Council's Trading Standards team has issued an alert for bank customers in the area regarding scam calls being received by some residents.
While the scammers currently appear to be targeting the Aboyne area, it is possible they will move onto other local areas.
Customers have been contacted by telephone and advised that fraudulent activity has been noticed on their account.
To safeguard it they are instructed to delete their mobile banking application from their mobile device and the fraudsters then upload their own software, which gives them access to customers' full bank details.
A council spokesperson said: "The phone number the scammers use to contact the customers is the same or similar to the number on the back of bank cards which gives it added validity, however banks advise this would never be used to contact customers.
"Unfortunately some customers have already been scammed out of large sums of money."