A rescue operation was under way on Tuesday to rescue a pod of pilot whales stranded on sandbars off Australia's southern island of Tasmania state.
About 270 whales stranded on Monday on two sandbars near the west coast town of Strahan.
Marine Conservation Program Wildlife Biologist Kris Carlyon estimated a third of the pod were likely to have already died.
Tasmania Parks and Wildlife Service manager Nic Deka said marine specialists and rescuers were trialing rescue efforts to determine the best rescue method.
"We'll be trying to free some whales this morning and if we're met with the methods we've settled on, we'll keep doing that, if not, we'll adapt it and do different things to try and get a better result," Deka told reporters.
Carlyon said rescuers will try and refloat some whales and then assess their behaviour.
"This entire operation, a lot of it depends on how these animals respond once they got water underneath them and are free-floating. So, that's the first step, get a few animals off, assess behavior and that will determine where we go to from here," he said.
Officials said the rescue operation could take days to complete.