Invercargill police were wrong to use a police dog to pull a man from a car after he'd failed a breath test, the Independent Police Conduct Authority has ruled.

Officers stopped a speeding car on Teviot Street at 1am on 18 October, 2020.

The driver failed an on-the-spot breath test but would not co-operate when police tried to take him to the station for an evidential breath test.

According to the IPCA report, the incident quickly became very hostile and two passengers shouted abuse and gang slogans at police.

"The rear passenger spat at police, while the front passenger got out of the car and confronted officers," the report says. Both passengers were arrested during the incident.

A dog handler and other officers came to help. After about 15 minutes, two officers tried to pull the driver from the car, but he resisted and was verbally abusive.

The dog handler then commanded his dog to bite the driver. It bit the driver’s arm and pulled him from the car.

The driver was taken to the ground and handcuffed. He received puncture wounds to his left bicep, facial grazing, and other scratches and bruising.

The driver complained about the use of the dog, and that he was pushed to the ground causing him to hit his head.

The dog handler defended his actions during the fractious arrest to the IPCA.

He told the Authority it was a gang vehicle: "I've never, ever, ever stopped a gang car that hasn't had a weapon in it, whether it be a gun, a knife, an axe, a piece of wood with a nail in the end.…"

These weapons are often on the floor of the car, or in side pockets, and therefore out of sight, he said.

The handler said the driver was assaultive, loud and of large build. "Who knows what skills he has, who knows what potential weapons he has," the officer said.

Passengers were moving freely around the car, and were unpredictable and aggressive, he said.

But the IPCA found that the use of the police dog was unjustified in the circumstances, IPCA chair, Judge Colin Doherty, says.

"We also found that the dog handler kicked the driver on his arm and on the side of his body while he was on the ground, and this was not justified," Doherty says.

"In this case, the driver had been pulled over for a driving offence and did not pose a threat to the public with the car immobilised and surrounded.

"He was being physically resistant and verbally aggressive but sufficient officers were present to deal with him and the two passengers.

"Other tactical options, such as continued negotiation or pepper spray, were preferable to using a police dog capable of inflicting serious injuries. To use a police dog in these circumstances was an overreaction."

The IPCA also found the dog handler didn't give the driver sufficient warning that he would set the dog on him.

The Authority completed its investigation into this incident in July 2021 but delayed the release of its public report until after the conclusion of related court proceedings.

The incident was captured on cell phone footage.

Acting Southern District Commander Mike Bowman says police have noted the findings.

The dog handler has pleaded guilty to a charge of injuring by an unlawful act.

"Any officer whose actions are potentially criminal will be thoroughly investigated and held to account," Bowman says.

"There remains an ongoing employment investigation, and for that reason we are not in a position to comment further at this time."

It's the second time in a week that the IPCA has ruled against the police for the use of a police dog.

It found another officer was wrong to use a dog to catch a young person who was running away after abandoning a stolen vehicle, in August 2021.

The youngster was bitten by the dog and needed hospital treatment. The IPCA's report also found the dog handler likely used derogatory language towards one of the young people fleeing the car.

The location of the incident was not identified in the report.