The Department of Conservation (DOC) is being criticised for its handling of the euthanising of eight pygmy whales in the Far North.
The whales were transferred to the east coast to be refloated after stranding on Ninety Mile beach,.
But the effort proved hopeless and they were shot dead before rescuers, including children, were cleared from the beach.
Volunteer Tesha Winks said of the incident, "We brought it up and they said, 'Stand back, we're going to euthanise it. We stood a metre back and everyone was standing around and a guy came over with a gun.
"I turned to the kids that I was with and I said, 'OK - it'll have a silencer, so just face your back and it’ll be OK.' And it didn't. It was really loud, so it was two loud shots into the whale."
Whale rescue experts say the process was careless.
Whale Rescue's Jo Halliday, who has been helping stranded whales for over three decades, said she has never seen a refloating attempt end this way.
"Someone should've cleared that beach way before that shooting was going to happen. I mean, for people to be witnessing that and to be standing so close is a really scary thought," Ms Halliday said.
"I would be frightened that if that bullet had ricochet off that bone or anything like that. Those people were way too close."
However, DOC is adamant that protocol was followed.
DOC marine ranger Cat Peters said, "Prior to doing anything, we confirmed everyone was happy with the safety and that people were behind a cordon".
However, Ms Winks said, "A lot of people I spoke to were distraught and shocked – just shocked - at the whole process of it."
DOC admits that euthanising animals can be distressing and staff have been visiting some of the local schools to talk to children who were on the beach that day.
It says it will try to do a better job in future, as well as advising rescuers about the harsh reality of euthanasia.