Police say a bone discovered in water off Byron Bay in northern New South Wales is human.
The bone was found by a scuba-diving instructor near the Wollongbar shipwreck on May 6.
Byron Bay police officer Matt Kehoe said it was sent for further testing.
"We've had some forensic examination done and it has determined that bone is a human bone," Chief Inspector Kehoe said.
"We've got ongoing forensic examination to identify the origins of the bone and to compare that with any of our known missing persons."
Police divers carried out a further search of the area around the shipwreck last weekend and discovered more items of interest, which they are yet to disclose.
Chief Inspector Kehoe said the bone was a substantial size and hadn't been in the water for long.
"From the initial forensic examination it does appear that bone has only been in the water for a short period of time, being either weeks or at most a couple of months," he said.
Diver reveals discovery
Master dive instructor Jason Baker said he was conducting an open water dive course with two students at the wreck when he noticed the bone protruding out of the sand.
"This object was quite clean, angular and a light yellow colour and it really caught my eye," he said.
"I had a real sense it was human.
"It looked unlike any animal bone I had found."
Mr Baker said he used a dive knife to remove it from the sand.
He believed it was a lower leg bone.
"As soon as we finished the dive I took it to the Byron police station to hand in the object," he said.
"I think all of us were cognisant there have been quite a few missing persons undiscovered here."
He said he had previously found unusual items such as pearls and World War II wreckage.
"But this has really sat with me more deeply," he said.
"Because of the domino effect of what it could mean for people with missing ones."
Missing swimmer
Chief Inspector Matt Kehoe said the most obvious avenue of inquiry would be whether or not the bone belonged to a Columbian national who went missing in the Byron Bay surf in March.
"We have obtained a DNA sample that we would be able to link from that missing Columbian male, so that will be one of the first avenues of investigations we will pursue," Chief Inspector Kehoe said.
A multi-agency operation was launched to search for the man, who went missing after struggling in the surf at Main Beach.
A swimmer attempted to assist at the time but was overwhelmed by the conditions.
The search involved vessels, drones and a helicopter as well as ground searches.
Chief Inspector Kehoe said it could be weeks before they received results from the forensic tests.
"It's not quite what we see on television and it does take some time," he said.
"It's difficult for family because they are obviously keen to find out any results."
