READ MORE:
• Police car 'smashed' in car chase through Rotorua streets
• Police chase on Northern Motorway: Driver arrested after going the wrong way
• Police chase: Fleeing driver crashes into parked cars in Christchurch
• Three people arrested after car chase
The 13-year-old alleged that he was dragged from the car and punched and kicked by police during his arrest.
The IPCA outlined the incident in its decision.
"The fleeing vehicle had stopped very close to the motorway barrier and as the officer pulled the boy from the car, the boy's head hit the barrier, causing cuts and bruising," said IPCA chair Judge Colin Doherty.
"The officer took the boy to the ground and punched the boy two or three times in the ribs before handcuffing him.
"The officer said the boy would not release his hands from under his body, so he used mid-strength punches to get him to release them."
The IPCA found the officer could have used more care in removing the boy from the vehicle, but the injuries to the boy's head were not intentional.
Judge Doherty said he was satisfied that the boy was not punched in the head or kicked while he was on the ground.
But he did not accept the officer's explanation that it was necessary to punch the boy in the ribs while handcuffing him and found that force was unjustified.
"The authority found that the officer who had removed the boy from the front passenger seat of the stolen vehicle had been unable to see inside because it had tinted windows,
there was no street lighting, and police lights were 'backlighting' it," he said.
"He was therefore unaware that he was dealing with a child, and the level of force he used to pull the boy from the vehicle was intended for a larger and heavier person.
"This resulted in a degree of momentum that caused the boy to hit the nearby motorway barrier and suffer cuts and bruising to his face."
The boy was arrested for being in a stolen vehicle and for breaching a bail condition relating to a previous incident.
He was held in police custody overnight and seen by a doctor the next morning before
being released to the care of Oranga Tamariki.
The following day, he and his mother went to a police station to complain about the force used.
Judge Doherty said the police were justified in arresting the boy and detaining him in custody until he could be released into the custody of Oranga Tamariki.
However, they failed to arrange immediate medical attention.
The youth had told officers he did not need a doctor.
"However, given his age and the nature of his injury, police should have arranged this anyway, and neglected their duty of care in failing to do so," said Judge Doherty.
Police acknowledged the IPCA decision.
"Our officer also had to use force to restrain the offender, the IPCA found this was not justified. However, I support his actions given the complex and fast-moving situation our officers were faced with," said Counties Manukau District Commander Superintendent Jill Rogers.
"The teenager was offered medical treatment on a number of occasions by our staff but we accept that given the offender's age, they could have considered arranging for him to be seen by a health professional."
Rogers said police dealt with volatile situations on a daily basis and did their best to handle each incident appropriately.
"We say it all the time but our staff deal with unpredictable situations every day and in the moment of high-pressure situations they have to make quick decisions with the information available to them.
"They also have to ensure that they reduce any risk to themselves, their colleagues and the wider public.
"Police carried out our own investigation into this incident and found the arrest and force used was justified."