At least 14 dead sperm whales have washed up on King Island, north of Tasmania.
The whales appeared to be young males and were already dead when they washed ashore on Monday afternoon, Tasmania's Department of Natural Resources and Environment confirmed on Tuesday.
Wildlife biologists and a vet are travelling to the island to investigate, while Parks and Wildlife Services staff are on site monitoring the situation.
Checks on whether there were any other whales in the area were also conducted from the air.
"It is possible the whales were part of the same bachelor pod - a group of younger male sperm whales associating together after leaving the maternal group," a department spokesperson told AAP in a statement.
"Members of the public are reminded it is an offence to interfere with protected wildlife, including being in possession of parts of a dead whale, and are asked to keep their distance."
Surfers and swimmers were also asked to avoid the immediate area as the carcasses may attract sharks.
Conservation and technology expert Dr Vanessa Pirotta said King Island had been the scene of various strandings over the years but what caused them remained "a complete mystery".
"We simply do not know why this happens," she told ABC News.
"That's the million-dollar question every time this kind of event happens."
It was only two years ago that hundreds of whales died after being stranded on Tasmania's west coast.
The 470 long-finned pilot whales were found beached on sandbars at Macquarie Harbour in September 2020 in what was the biggest mass stranding on record in Australia.
After a week-long rescue effort, only 111 whales could be saved, leaving authorities to dispose of more than 350 carcasses.
Dr Pirotta said the latest event may have been triggered by a navigation error or the group following one whale heading towards the shore.