Most of the whales had died by the time New Zealand Department of Conservation officials got to the remote Doughboy Bay area.

Conservation officials said the remoteness of the site, at Stewart Island, off the southern tip of the New Zealand mainland, hampered all efforts to save the others.

Southland conservation officer Lou Sanson said: "Our marine mammal specialists say this is one of the largest strandings ever recorded."

'Distressing scene'

When the conservationists arrived at the scene they shot about 40 whales on humanitarian grounds.

Mr Sanson said: "The surviving whales were so distressed it was better to put them out of their misery.

"It was a distressing scene for staff but it's an entirely natural event which has been happening for thousands of years."

Samples of whale tissue, liver and teeth are to be examined marine scientists to try to help find out why whales swim into deadly shallow waters.

One theory for the beachings is that a single whale is beached while chasing food and its distress cries attract others in its pod.