Wellington: Hundreds of volunteers have helped rescue some 100 pilot whales that were stranded on a beach close to Nelson, on New Zealand’s South Island, according to authorities on Saturday.

The rescued whales were part of a group of 400 cetaceans that were beached in the area, 300 of whom died after attempts to refloat them failed, Efe news reported.

Pilot whales can grow up to 6 metres in length and weigh over three tonnes. Scientists are yet to find out what brought these whales to the beaches.

The latest incident in New Zealand was first reported on Friday evening, but conditions were too dangerous at the time to launch a rescue operation, the BBC reported.

The surviving whales were kept alive after “being kept cool, calm and comfortable” by medics and members of the public.

A human chain stops Pilot whales from returning to shore during a mass stranding at Farewell Spit on February 11, 2017. Photo: AFPOpen

New Zealand has one of the highest stranding rates in the world, with about 300 dolphins and whales ending up on beaches every year, according to Project Jonah.

Many of these incidents happen at Farewell Spit. Experts say its shallow waters seems to confuse whales and hinder their ability to navigate.

In February 2015 about 200 whales beached themselves at the same location, of which at least half died.