An Australian crocodile farmer who found an orthopaedic plate inside a crocodile's stomach said on Thursday he had been told the surgical device was from a person's body and had been contacted by relatives of missing people anxious for clues.

Koorana Crocodile Farm owner John Lever found the plate inside a 4.7-metre (15-foot- 5) croc called M.J. during an autopsy in June at his business near Rockhampton in Queensland state.

He initially wasn't sure if the unusual find had been part of an animal or human. But he said since making photos of the plate public, he had been told it was a type used in human surgery.

Lever estimated that M.J. was 50 to 70 years old when he died. M.J. could have eaten the bone that the plate had been attached to by six screws 50 years ago, he said.

All remnants of human tissue attached to the plate had been long digested before M.J. died several months after losing a fight with another croc.