A US travel blogger has described the trauma she experienced when she came across hundreds of stranded pilot whales on Stewart Island.
Liz Carson was on a five-day-hike with her friend when they found the whales on Mason Bay as they made their way back to their camp.
"When we realised the horror of what we were seeing, we dropped everything and ran straight into the water," she wrote in a post on Instagram.
What is usually a long stretch of remote beach quickly became the site of a desperate struggle for life on Saturday as 145 whales fought to get back in the surf.
"Desperately we grabbed their tails and pushed and yelled before we got hammered by them thrashing around," Ms Carlson says.
"It was useless, they were so big and heavy and the realisation we could do nothing to save them was the worst feeling I've ever experienced."
Her friend Julian Ripoll ran almost 15km to alert Department of Conservation (DOC) staff to the tragic scene.
Within an hour and a half, the alarm was raised. Ms Carlson stayed with the whales until dark, sitting with them trying to comfort them, throwing water over their dry bodies and trying to help refloat them.
"I'll never forget their cries, the way they watched me as I sat with them in the water, how they desperately tried to swim but their weight only dug them deeper into the sands," she says.
"Saturday night was the worst night of my entire life."
Her heart was completely broken when she realised they could not be saved.
"I knew they would inevitably die. I sank to my knees in the sand screaming in frustration and crying, with the sound of dozens of dying whales behind me, utterly alone.
"I'll never be the same after this."
Half of the whales had already died by the time they DOC arrived and, due to the condition of the remaining whales, the decision was made to euthanise them.
The stranding is the second to have occurred over the weekend. In Northland, a sperm whale was found beached and died overnight on Saturday. And on Sunday 10 pygmy killer whales were found stranded at 90 Mile Beach.
It is unlikely the strandings are linked, DOC says.
In 2011, two tourists found a pod of 107 pilot whales beached and dying on Mason Bay.
Marine mammal strandings are a relatively common occurrence in New Zealand. DOC have responded to an average 85 incidents a year - mostly single animal strandings.