At least 380 whales have died in a mass stranding in southern Australia, with rescuers managing to free just a few dozen survivors.

Nearly the entire pod of 460 pilot whales stuck in Macquarie Harbour, on the west coast of Tasmania, has now died.

"We can confirm that 380 whales are dead," Tasmania's Parks and Wildlife Service manager Nic Deka said.

 

"There's around 30 left still alive but the good news is that we have saved 50," he said.



The first of the whales were found on Monday, sparking a major effort to free them from a sandbar only accessible by boat.

It is the largest mass stranding ever recorded in Tasmania, and likely the biggest in the country's history.

A rescue crew of 60 conservationists, skilled volunteers and local fish farm workers has concentrated efforts on a group of whales partially submerged in the water.

The rescuers have spent two days wading in the cold shallows to free the still living creatures, using boats fitted with special slings to guide them back to the open ocean.

They are now racing to free as many of the 30 remaining live whales as possible.


The whales have been found stranded up to 10 kilometres apart, and officials have now expanded their search area to see if more of the mammals are stuck nearby.


"The good news is the majority of whales that were rescued are still out in deep water and swimming," Deka said.

"They haven't stranded. So we've been more successful than not."

The causes of mass strandings remain unknown -- even to scientists who have been studying the phenomenon for decades.