Scammers are pretending to be from HMRC in an attempt to trick people into giving up their cash, police say.
Officers in Bury have warned about bogus callers using the scheme to try and defraud people using premium phone numbers.
Residents receive a call and are told that if they do not follow the instructions a warrant will be issued against them.
But, when they click to follow the request it transfers them to a different number and charges them for the call.
In a post on Facebook, a spokesman for GMP's Bury team asked people to make their relatives and friends aware of the scam.
They said: "We are having reports of scam callers calling from 0300 2005368 and stating they are from HMRC.
"The recorded message then goes on to say you owe money and to press button 1 on your phone otherwise a warrant will be issued for your arrest.
"Pressing button 1, this will be a premium number which charges large amounts.
"HMRC does not contact people by phone, only by letter, please make any vulnerable or elderly persons, family and neighbours aware."
Anyone with information about scams can contact police on 101.
Alternatively, use the Live Chat feature on www.gmp.police.uk.
