A fatal police chase two years ago, which has been the subject of four investigations, was badly managed by police - but there is no evidence of a "cover up", the Police Complaints Authority has found.

Auckland teenager Erin Burgess, 18, and motorcyclist Kuran Brunton both died in the crash south of Whangarei on May 12, 2003, which occurred at the end of a prolonged chase where officers pursued Mr Brunton at speeds approaching 200km/h.

A coroner's court hearing in Whangarei revealed that throughout the chase, police staff at the communications centre had no idea where some of the police cars were.

One car had been chasing when it was supposed to be parked on the side of the road.

An initial police investigation found police officers complied with police policy, but after the coroner's report, the Police Commissioner's Office appointed Detective Superintendent Malcolm Burgess to re-investigate the crash and report to the Police Complaints Authority.

In the report released yesterday, Judge Ian Borrin concluded that "the management and execution of the pursuit was defective".

"In my clear view, the speeds attained by the police vehicles were excessive and the pursuit should have been abandoned," he wrote.

The family had been concerned that police officers had "ignored and disobeyed instructions" and then "lied to cover up their actions".

However, Judge Borrin said there was no evidence to support the assertion that the initial investigation was either "incompetent" or a "cover up".

In fact, police had been open to involving external experts and witnesses and sharing information with the Burgess family.

The family's contention that if police had not been in pursuit, the "accident would not have happened", was impossible to prove, he said.

Mr Brunton was already speeding at 47km/h in excess of the speed limit before police began chasing him, and it was not known what effect, if any, the pursuit had on his speed.

An autopsy revealed the presence of methamphetamine and cannabis in his blood.

The authority agreed with the coroner that the "primary cause of this tragedy is readily established as the grossly careless and dangerous driving of Kuran Brunton".

Police have since adopted a formal pursuit abandonment procedure, and set up more stringent driving training for officers.