Volunteers have formed a human chain to try and save stranded New Zealand whales. 

They have braved the threat of sharks and stingrays as they continue their attempts to save pilot whales stranded in New Zealand.

More than 400 whales had swam aground at a remote beach on Farewell Spit at the tip of the South Island - and about 300 of them were already dead when they were discovered.

On Friday, rescuers successfully refloated the surviving whales - but many of them beached themselves again overnight.

Now, more than 100 volunteers have formed a human chain in an attempt to encourage them to swim into deeper water and stop them from returning to the bay.

Officials are now turning their attention to the grim task of disposing hundreds of carcases. Farewell Spit has been described as a whale trap, as its long coastline can be difficult for whales to navigate away from.

It is believed whales end up stranded as they try to escape predators, chase prey too far inland, or try to protect a sick member of their pod.

Friday's stranding was the third-biggest in New Zealand's history. The largest one on record was in 1918, when about 1,000 pilot whales came ashore on the Chatham Islands.