“A pod of approximately 230 whales has stranded near Macquarie Harbor,” said the state’s Department of Natural Resources and Environment.
“It appears about half of the animals are alive.”
Aerial images showed a devastating scene of dozens of black glossy mammals strewn along a stretch of beach where the frigid southern ocean meets the sand.
Almost two years ago to the day the area was the scene of another mass stranding involving almost 500 pilot whales. Just over 100 survived.
The causes of mass strandings are still not fully understood.
Scientists have suggested they could be caused by pods going off track after feeding too close to shore.
Pilot whales are highly sociable and can follow podmates who stray into danger.
Officials said marine conservation experts and staff with whale rescue gear were en route to the scene.