More than 150 whales have died after beaching themselves in southern Australia, with many sustaining deep cuts after thrashing onto rocks, an official said Monday.

The long-finned pilot whales were discovered trapped on a rocky beach in the remote west coast of Tasmania state on Saturday but early aerial reports suggested that only 72 had died.

Subsequent investigations revealed that many more of the giant animals had perished, Warwick Brennan from the state's Department of Primary Industries and Water said.

"155 are dead," Brennan told AFP, adding that 32 more animals had been successfully shepherded offshore and had a good chance of survival.

Brennan said many of the whales had been badly injured after thrashing heavily on the rocky shore of Sandy Cape.

The beaching follows the deaths of more than 50 pilot whales, deep water animals which can reach more than seven metres (20 feet) in length and weigh up to three tonnes, after they became stranded on a nearby beach the previous weekend.

Brennan said Australia's southern island of Tasmania often experienced whale beachings, a phenomenon so far unexplained by science.

"We get a bit nervous when they come into shore," he said.

Since 1900 there have been 75 whale strandings recorded in Tasmania, which accounts for 80 percent of such events in Australia, with several involving more than 200 animals, Brennan said.