A supplied image obtained on Monday, November 26, 2018, shows about 145 pilot whales stranded near Mason Beach on New Zealand's southern-most island, Stewart Island, over the weekend. (AAP Image/Department of Conservation)
More than 140 pilot whales have died after becoming stranded on a remote beach in New Zealand's far south.
The 145 whales from two pods were discovered by hikers near Mason Bay on Stewart Island on Saturday night and about half were dead by the time conservation staff had arrived, the Department of Conservation says.
The hard-to-reach location, lack of nearby rescuers and worsening condition of the whales meant the rest had to be euthanised, department operations manager Ren Leppens said.
"Sadly, the likelihood of being able to successfully re-float the remaining whales was extremely low," he said.
"However, it's always a heart-breaking decision to make."
Pilot whales have a reputation for stranding, thought to be partly due to their preference for steep landforms and sloping underwater areas, which may interfere with their sonar.
Whale strandings are relatively common in New Zealand and authorities deal with about 85 each year, although most are small.
Early last year, more than 300 of the animals died and 100 more were beached at the top of New Zealand's South Island, in what was one of the country's worst strandings. More than 100 died in a mass stranding at Mason Bay in 2011.
© AAP 2018