Police officers chasing a speeding car, which later crashed killing four people, had to be told to pull out twice because they missed the first order.
The Independent Police Conduct Authority has cleared the officers involved in the chase which ended shortly before Dominic Stehlin, who was 19, and three of his passengers were killed.
The police watchdog has also found that Mr Stehlin had alcohol and cannabis in his system and was a suspended driver.
At about midnight on 11 May last year, Mr Stehlin was spotted by two officers driving along Great South Rd in Papatoetoe. He was doing about 70km/h in a 50km/h zone and was seen going through a red light.
The officers began chasing and Mr Stehlin drove up to 160km/h on State Highway 20.
The chase was being monitored by the central police communications headquarters (North Comms) which eventually told the officers to pull out.
About a minute and a half later, a patrol car ahead of Mr Stehlin on State Highway 20 made contact with North Comms.
North Comms reply was that Eagle, the police helicopter, was on its way. The officers were told: "Don't initiate anything at this stage".
One of the officers in the car, identified only as Officer C, told the authority he didn't remember hearing that order.
A short time later on Massey Road, the policeman known as Officer D reported Mr Stehlin's speed as 70km/h in a 60km/h zone, and about five seconds later North Comms told them to abandon the chase.
However, Officer D said he didn't hear the order because he was telling North Comms that Mr Stehlin was using the opposite lane to overtake cars and they were going to pull out of the chase.
North Comms repeated the order to pull out, which Officer D acknowledged, and they turned off their sirens and flashing lights and slowed down to the 60km/h speed limit.
The Independent Police Conduct Authority says the officers were unable to pull over because there were no parking spaces. About 500 metres down the road, they found Mr Stehlin's car. He had lost control, collided with the kerb before turning sideways and slamming into a parked ute.
Mr Stehlin and his passenger Uesetini To'o To'o died at the scene. Two others - George Lomia and Viane Gaga died later in hospital.
A police crash investigator found Mr Stehlin had been driving up to 154km/h when he crashed and the impact speed with the ute was up to 100km/h.
Mr Stehlin was an unlicensed driver and had been forbidden to drive in February this year. Toxicology reports show he had 70 milligrams of alcohol per 100 millilitres of blood. The legal limit for under 20s is zero. Traces of cannabis were also found in his blood.
The IPCA found police had complied with the law and police policy. Chairperson Judge Sir David Carruthers says there is a conflict between the prescriptive nature of the relevant policies around police chases and the reality of fast-paced chases.
Police have declined to be interviewed. However in a statement, Counties Manukau District Commander Superintendent John Tims says they accept the authority's findings. He says police send their deepest sympathies to the four families who lost loved ones in this crash.
Mr Tims says police are highly trained and is comfortable that in this high-pressure situation, his officers acted according to police policy.