Ontario's police watchdog says its toll-free number is being used in fraudulent calls that ask people for their social insurance number.
The Special Investigations Unit says that in some cases the person answering the call is told that there is something wrong with their social insurance number.
The SIU says the person is then told they will be charged or jailed if they don't continue with the call.
The agency says it does not contact people over the phone for such personal information.
It is asking anyone receiving such calls to report them to the Canadian Anti-Fraud Centre and Canada's Do Not Call List.
The SIU says the calls appear to be coming from 1-800-787-8529.