An animal welfare group is to lay a complaint with police after being sent a video of teenagers stoning a kitten to death.

Paw Justice put the video online after it was sent to them by an Invercargill resident in a bid to try to identify the teenagers.

It shows young people throwing a large rock at the kitten until it dies. It has been viewed more than 150,000 times since it was posted this evening.

Within three hours of being online it had been shared nearly 5000 times and has more than 6000 comments.

"It's one of the most disturbing videos I've seen in my career at Paw Justice - it's just horrific," said Craig Dunn, the group's co-founder.

"A girl has a kitten and they are deciding where to kill it - on the concrete or the grass.

"A male throws a large boulder and drops it on the head," he said.

In the video, the kitten tries to escape before being attacked again.

"It was so casual and blasé - there was no empathy, no consideration, nothing towards it."

Mr Dunn said the huge online response shows people were disgusted with this type of behaviour.

"For sadistic behaviour like this, they need to be brought to law and made accountable."

Many people have contacted Mr Dunn believing they know the culprits and he said he will speak with Invercargill police today.

Wilful ill treatment of animals is punishable by up to five years in prison.