Another 250 pilot whales have beached on the Chatham Islands on Monday, the second mass stranding in the last four days.
Project Jonah New Zealand - a charity group focused on whale and dolphin protection and rescue - reported the news of the pilot whales being stranded on Rangiauria/Pitt Island, about 40km south of the stranding over the weekend.
The Department of Conservation (DoC) said they have sent a team over to the island to assess the situation.
"As DoC does not actively refloat whales on the Chatham Islands due to the risk of shark attack to both humans and the whales, the surviving whales were euthanised by our trained team to prevent further suffering," a spokesperson for DoC.
"This decision is never taken lightly, but in cases like this, it is the kindest option."
It comes after 215 whales were stranded on Chatham Island on Friday - many of which died.
Marine Biologist Karen Stockin told AM on Tuesday with Rangiauria/Pitt Island being isolated, makes it a great marine environment for many apex predators like great white sharks.
"As you can imagine, when these whales strand, often there can be a range of injuries and blood loss from the whales themselves and this can attract marine predators to the area. So it's generally not considered safe for humans to be in the water in the same way you would see off say Farewell Spit in Golden Bay," Stockin told AM co-host Melissa Chan-Green.
Stockin said it's not looking good for the whales currently stranded.
"In New Zealand, we pride ourselves in being able to engage and to undertake rescue attempts wherever feasible, possible," she said.
"The reality is, with the very small population sizes on such islands and the inability to get trained medics there in a timeframe that would be suitable for animal welfare or survival perspective, it really is unfortunately often the case the endings are never happy."
Stockin said conservationists are trying to figure out how to prevent these mass strandings from happening again.
"There are lots of discussions that have been had around, are their technologies, are there acoustic pingers or things that we could use to try to deter whales using those," she said.
"The problem is in many cases, those whales are in those regions for prime activity, for feeding or breeding or whatever the case may be. So it's always a real clear risk you run of actually driving animals out of key habitat that's actually crucial to their survival."
AM co-host Ryan Bridge asked Stockin once the first whale gets into trouble, why do the rest of the group fellow.
"The thing about pilot whales is they are one of the most highly socially complex mammals you can find, orca is another example, but any of these species that form these really strong social bonds means when an animal gets into trouble, there's always a higher risk that it will potentially bring the rest of the pod in," she explained.
"That's half the battle when you're actually undertaking interventions of rescue to try and refloat animals is to be sure that if you do have an injured or a debilitated animal, that's not going to survive, you have to think about what its chances are of bringing in other animals."
Watch the full interview with Karen Stockin above.
