A leg bone found at The Spit on the Gold Coast is being examined as families of missing people contact police.

A leg bone found in a popular Gold Coast waterway is human, while three others belong to animals, forensic examinations have confirmed.

Families of missing people have contacted police, hoping the grisly discovery may provide answers.

Fisherman Gavin Studwell, whose homemade boat capsized in 2012, and mother-of-two Novy Chardon, who disappeared in February last year, are among those who have gone missing on the Gold Coast.

But police aren’t adding to speculation about who the leg bone may belong to.

“They are keeping an open mind on that matter,” a police spokesman told AAP.

Recreational diver Drew Valentine found the human leg bone off The Spit last Thursday and handed it into police at the weekend.

He found an animal bone nearby on Tuesday as police searched the area.

Police divers found the last two animal bones during a rock wall search on Wednesday.

“Only one bone, the first one, is proven to be human,” the police spokesman said.

Investigators will monitor seabed conditions in the area during the next few days to determine if another underwater search is necessary.

The human bone is being forensically examined at Brisbane’s John Tonge Centre.