More than 100 pilot whales and bottlenose dolphins are dead after being stranded on the Chatham Islands, with 26 of them having to be euthanised.
The Department of Conservation was notified of the mass stranding on a remote Chatham Islands beach at midday on Sunday.
Ninety-seven whales and three dolphins died in the stranding, and 26 of the animals were alive but very weak.
DOC biodiversity ranger Jemma Welch said the 26 were euthanised due to rough seas conditions, and the almost certainty of the stranding attracting great white sharks to the area.
She said a further two whales had stranded on the beach when DOC staff visited the site on Monday morning, and these whales also had to be euthanised.
Hokotehi Moriori Trust and Ngāti Mutunga o Wharekauri Iwi Trust joined DOC staff on Sunday and performed a karakia to honour the spirit of the whales, which will be left to decompose naturally.
Commercial diver and photographer Sam Wild said the whales stranded at a northern beach on the main Chatham Island.
He said it was an horrific and emotional scene.
Locals had put out word of the stranding the day before, he said.
"I mean the Chatham Islands ... is a pretty remote place, their beaches are pretty remote, there's not a lot of people around them so when they were eventually found the radio call went out to a few people, cause there's so many divers around the island, myself included."
Wild said the diving community is told to stay out of the water when there has been a whale stranding because the Chatham Islands has a population of great white sharks which may come in to feed on the carcasses.
"So stayed out of the water and took the camera instead and yeah it was pretty sad to see."
Wild said whale strandings happen every year or two on the islands.
DOC's website describes the Chatham Islands as a mass stranding "hotspot" for pilot whales, adding that the biggest recorded pilot whale stranding was when an estimated 1000 whales stranded in the Chatham Islands in 1918.