Kier, which looks after council properties in the city, said households had been approached in the Manor and Norfolk Park areas.

Kier spokesman Phil Oades said the callers had used fake identification badges.

Sheffield Homes, which manages the council’s housing stock, said all callers should be double-checked.

Oades said: “A lot of our work involves visiting people at home and we need to ensure tenants feel safe answering the door to Kier staff.

“It is worth reminding them to check the identification badges of all callers, not just those from Kier.”

A Sheffield Homes spokesman added: “We, and our construction partners, carry out many visits to tenants and all of our staff carry ID so please ask to see it.

“If you are still not sure about the caller you can ask the Repairs Service Centre staff to give you a password that Kier’s workers will quote when they visit you.”