This photo, released by the Department of Conservation New Zealand, shows a pod of beached killer whales at the remote Blue Cliffs Beach on the far south coast of the South Island, on February 12, 2014

A pod of nine killer whales died on Wednesday in a rare mass stranding on the New Zealand coast, in a loss conservationists said was a major blow to the local orca population.

The pod, comprising eight adults and one juvenile, beached themselves at the remote Blue Cliffs Beach on the far south coast of the South Island, Department of Conservation spokesman Reuben Williams said.

"By the time we were able to reach them they were all dead," he told AFP.

Mass strandings of pilot whales are common in New Zealand but Williams said it was unusual for so many orcas to run aground at the same time.

"We don't know the reason why they stranded (themselves)," he said.

"It's unfortunate and will have quite a major impact on the national population which is sitting around 200 animals."

Williams said the carcass of one whale had been retrieved for research and local Maori people, who consider the animals sacred, were being consulted about disposing of the rest.

Orcas, the largest members of the dolphin family with no natural predator, can grow to lengths of up to 9.8 metres (32 feet).

The black-and-white animals are the most widely distributed cetacean species in the world. They are highly sociable and live in pods of up to 50 members.

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© 2014 AFP