Police officers used excessive force when they used a dog to catch a woman who had been a passenger in a stolen car, the the Independent Police Conduct Authority has found.
The woman received substantial injuries to her right arm and spent three days in hospital after the incident in Paeora in April last year.
Officers had been chasing the car and the people in it abandoned it and tried to flee.
A dog handler was called in to try to catch them, and after some time the woman was spotted crouched down on the top of a bank in a paddock.
What happened next was disputed, the authority said.
The woman said she made herself visible and put her hands above her head to show that she was surrendering.
The dog handler said that when challenged by him she ran away into the paddock.
The woman, however, was adamant that she did not run, but stayed still on the ground as instructed, the authority said.
Regardless, the dog handler released his dog and it bit her.
Authority chair Judge Colin Doherty said the police response was not proportionate.
"The female was a passenger in a stolen vehicle. She was giving herself up to police," he said.
"The use of the dog was neither proportionate to the circumstances or the offence she had committed or appropriate when she was surrendering. The female's injuries were substantial and required admission to hospital and surgical repair to her arm. The force used by the dog handler to apprehend the female was excessive."
Police have acknowledged the authority's findings and said that other tactical options could have, and should have, been used first.