Almost 90 of the 470 long-finned pilot whales beached near Tasmania have been rescued.

The official leading the operation; one of the largest strandings the world has seen revealed that the time-frame for being able to save the animals is running out.

It is thought that another 20 animals could be saved on Thursday - following that the operation would move towards easing the whale's suffering and the disposal of carcasses.

The pod of whales were first spotted on Monday stranded in an inlet off the coast of Tasmania - with more noticed on Wednesday.

Nic Deka, incident controller for the Tasmania Parks and Wildlife Service, said: "Beyond the next 24 hours, any remaining animals that are alive will be less viable."

Even if they were helped back to open water, the animals are now getting to the point where they would be too tired to swim if they are rescued.

Most of the whales that have been saved are now in deeper water, but there are worries more could be drawn to those still stranded.

With those that have been helped taken into account, authorities are working on a plan to deal with 380 whale corpses.

Mr Deka said: "Our preference is for disposal at sea, we're still taking expert advice as to exactly where the drop off point may be."

Euthanisation may be the most humane route to deal with the incident - as it could take weeks for the whales to die if left on the sandbank.

"For large whales very sadly, it could take weeks for them to die, and they get blistered in the sun, so you would be thinking about an ethical and humane thing to do," Mr Deka added.