A police chase that ended in a fatal crash outside Oamaru should have been abandoned earlier, the independent police watchdog says.
Luke Bradley Savigny (25) was jailed for five years seven months earlier this month before the High Court at Dunedin after pleading guilty to the manslaughter of 32-year-old Christopher "Chipper" Narayan Blair.
Savigny was drinking and using methamphetamine and cannabis before driving north from Dunedin on March 21 last year.
Police received multiple complaints from members of the public as the defendant drove erratically, crossing the centre line and exceeding the speed limit on numerous stretches of State Highway 1.
Shortly before 7am, police saw the defendant passing through Alma, weaving and veering into the wrong lane.
"When the offending vehicle failed to stop, the patrol unit pursued the fleeing driver from a distance," an Independent Police Conduct Authority (IPCA) decision said.
Savigny increased his speed to 130kmh.
A few minutes later the officer came across the wreckage.
The vehicle was split into two pieces at the intersection of Severn and Wansbeck Sts.
A subsequent investigation found Savigny had hit speeds of 150kmh when he lost control, skidding over a footpath, clattering into a 50kmh speed limit sign and colliding with five trees.
Neither man in the car was wearing a seat belt.
Blair died instantly, while Savigny was hospitalised.
A police investigation found the officer complied with policy at the time of the pursuit but "should have abandoned the pursuit at an earlier opportunity when they lost sight of the offending vehicle approaching the built-up area of Oamaru".
The IPCA said police had identified "several learning opportunities" for both the officer and communication staff involved to improve how they manage similar events in future.
The authority was satisfied with how the police conducted their review of the incident.