Warning: This article contains an image of a deceased dog, which some may find disturbing.

A puppy farm in northern NSW has been investigated by RSPCA NSW after animal activists claimed that they had found evidence of dogs living in "appalling conditions."

Cruel reality: Dogs in a pen at the NSW puppy farm. Credit:Debra Tranter

Bodies of deceased dogs were found around the property according to animal activist, Debra Tranter, who told Fairfax Media and the RSPCA about the property on Wednesday.

"One dog had been placed inside a dog food bag and left there to rot," said Ms Tranter, who is the founder of animal rights group Oscars Law.