An intellectually disabled Perth man is living in fear after he discovered neighbours stealing electricity from his home with an extension cord.

The man, named Shane, lives in a Homes West property in Gosnells in Perth's south-east and works regularly at Good Samaritan industries.

An extension cord runs from the power point to the neighbouring residence.

But his sister Cheree told 6PR's Oliver Peterson that the 53-year-old recently got a rude shock when he looked in his backyard.

"We just found out that one of his neighbours has put an extension cord over his back fence and has plugged it into his power point in his backyard," she said.