Residents are being warned about rogue traders purporting to be ex-offenders or former members of the army.
Norfolk Trading Standards has raised awareness of cold calling in the Harleston area with rogue traders trying to sell household products in large holdalls.
It comes after similar warnings were issued for the Hethersett area after three men were seen knocking on doors on the morning of Tuesday, May 26.
Stephen Maunder, from Norfolk County Council's trading standards department, said there has been an increase in reports of rogue traders as we head into the summer months.
Mr Maunder said they have already issued warnings about people offering roofing work, to cut trees or hedges and to pressure wash driveways this year.
There were also reports of men knocking on doors in Thorpe St Andrew at 3am this week.
If approached, residents should report it to Norfolk Trading Standards on 0808 223 1133 or to Norfolk Police on 101.
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