A police officer who fired 21 shots at a car which was trying to ram him was justified, the Independent Police Conduct Authority has found.
Police have acknowledged the finding, which relates to an incident in 2017 in Coromandel.
A Holden Commodore and a firearm had been stolen in the area in two separate incidents, and the officer had found the silver Commodore and pulled it over.
The officer was in the process of arresting the woman driving the Commodore when a male in a black Subaru drove into the open door of the police patrol car.
The Subaru then repeatedly tried to hit the officer, who took cover behind his car and armed himself.
He fired several shots at the vehicle, trying to incapacitate the driver, and the woman managed to get into it, and they sped off.
Police soon after caught up with both people, arrested them, and both were charged. No one was injured in the confrontation.
The authority ruled that, given the circumstances, the officer was justified in arming himself and in firing shots in self-defence.
IPCA chair Judge Colin Doherty said that "the man could not be stopped by any other means than the use of a firearm.
"The officer believed he was in a vulnerable position and had no realistic way of hiding or escaping," Judge Doherty said in a statement.
"The other defensive options available (such as baton, pepper spray, or Taser) would have been ineffective against an attacker using a car as a weapon."
Waikato district commander superintendent Bruce Bird said in a statement that "this was a fast and evolving situation in which the officer made judgment calls that were supported by the IPCA".
"The officer involved was extremely courageous and made all the appropriate notifications while this incident was unfolding," Mr Bird said.
"This was a very traumatic experience for the staff concerned and their colleagues, particularly in Eastern Waikato, who we continue to support."
The IPCA report also found that the officer involved should have put on ballistic body armour when arming himself, as per police policy.
Police said all recommendations made by the IPCA finding had since been implemented.