The offender usually cold calls the victim and tells them they are investigating their bank and the people who work there are corrupt.
As part of the investigation, they ask the victim to transfer or withdraw large sums of money.
A police spokesperson said: "A police officer would never ask you to withdraw money or transfer money to another account.
"This is a con.
"Please make sure you elderly or vulnerable loved ones are aware of this scam.
"If you think you’ve been targeted or want to report a fraud incident, please call Action Fraud as soon as possible on 0300 123 2040."