A teenager is undergoing emergency surgery after being hit by a bullet which ricocheted off an animal's head during a homekill which went wrong in north-west Auckland.

Police said the accident happened at 11.15am on a rural farm property on Peak Rd, Helensville, when a slaughterman reportedly shot a cow in the head.

The bullet ricocheted off the animal's head and hit the slaughterman's 18-year-old assistant in the shoulder.

The victim was flown to Auckland Hospital. Police have informed his family of the accident.

A hospital spokeswoman said the teen was in a critical condition this afternoon.

A spokesman from the police northern communication centre said police spoke to the slaughterman at the scene. He did not know if police had formally interviewed him.

Police were conducting a scene examination at the accident site which is understood to be near Gumboots Early Learning Centre.

They were also interviewing witnesses.

A police spokesman said the cow did not die from the initial gun shot, but was later shot dead by police.



He said the animal was knocked out by the first bullet but was still moving.



The spokesman said the slaughterman did not kill the animal with a second shot because he was concerned about his assistant.



He said police had not alerting the SPCA about the incident because the slaughterman "did not have evil intent".

Caregivers at the learning centre said the first they knew of the accident was when they saw a helicopter fly over.

A resident living on Peak Rd passed the accident scene, about one kilometre from the intersection of Peak and Old North roads, on her way home about 1pm.

She said a homekill van was parked just off the road and police were at the scene.

Both OSH and the Department of Labour had been notified and were also investigating.