Four children badly burned after a car they were in caught fire in the backyard of a Huntly house were sniffing fly spray, police have confirmed.

Huntly police Sergeant Neil Mouncher said the children -- aged between 12 and 15 -- were sitting in the vehicle, understood to be an old Range Rover, at the back of the Semple St property, when it caught fire about 10.45pm yesterday.

Three suffered serious burns to areas including their faces, hands and arms and were undergoing surgery at Waikato Hospital this afternoon.

The fourth victim suffered moderate burns.


"The four kids nipped out the back and sat in this wreck of a car in the rear of the house and were sniffing on fly spray. Apparently they spray it into a cloth and sniff it through the cloth. One of the four had a bright idea that they would light a match or lighter and it set the car on fire."

Mr Mouncher said the blaze would have been caused by a build-up of flammable gasses from inside the vehicle before a flashover has occurred.

At least three of the injured youths were visiting the property and from Hamilton, Gisborne and Auckland.

"When the police turned up they were all huddled together in the shower trying to cool themselves down."

Police would continue to investigate the incident over the next few days but he said it appeared to be a "tragic accident I believe rather than anything else". "It would be a different story if they intentionally tried to set fire to themselves but I don't think they'd want to be doing that very often."

As for sniffing fly spray, Mr Mouncher said it was "the last thing I would have thought you'd be wanting to sniff, considering it kills flies".

"I'd hate to think to what it does to your insides."

Fire Service northern shift manager Scott Osmond said the group managed to flee the burning vehicle before firefighters arrived at the scene.

The Fire Service was alerted to the blaze by surrounding neighbours.