Bexley Council is urging people not to divulge personal details over the phone after a recent fraudster tried to trick a woman out of money.
Trading Standards has revealed a resident was recently rung by a cold caller, who pretended they were from the council.
They told her she was entitled to a council tax refund and asked for her bank details.
She refused to give the details and informed the local Trading Standards team instead.
Bexley's cabinet member for community safety and leisure Councillor Alex Sawyer said: "Local councils never cold call, text or email residents requesting bank details.
"If refunds are due or there is any change to your bill, you will receive a statement through the post explaining the situation."
A Bexley Council spokesman said: "Anybody who has received such a phone call should report the matter to the Citizens Advice consumer helpline on 03454 040506."