Police have been told to revise their car chase policy following an investigation into a botched pursuit, which ended in a speeding motorcyclist crashing and sustaining a brain injury.

In 2010, motorcyclist Dion Batt, who was 34 years old at the time, drove through a 50kmh zone in an Auckland suburb at 100kmh, while he was on P, the Independent Police Conduct Authority said.

After a police pursuit, which lasted a total of 25 minutes and involved 11 police vehicles and a helicopter, Batt crashed into a traffic island.

He was severely hurt and sustained a brain injury which required long-term treatment.

An investigation by the authority into the chase, released today, found several events that occurred during the chase did not adhere to police policy.

In addition, the authority, which oversees police conduct, found the chase had poor command and control, and was "plagued" with communication issues.

On the evening of the chase, a police officer in Massey, West Auckland, saw Batt speed past and decided to pursue him for dangerous driving, the authority said.

The officer said he had started the chase because Batt was "driving like an idiot heading towards me".

The authority said the officer ended the chase after three minutes because the risks were too high, a decision the authority said complied with police policy.

A helicopter was then dispatched, found Batt within five minutes, and advised the Police Northern Communication Centre.

According to the investigation, three staff members at the communications centre on three different radio channels handled the event, causing "serious communication difficulties" between the centre and some of the police units.

"This contributed to confusion regarding a number of issues, including: the status of the pursuit (active or abandoned); which channel was running the incident; and the number of units involved," the authority said.

Because of the lack of communication, a West Auckland police unit set up an unauthorised road block, which Batt rode through before speeding away.

The staff member in charge at the communication centre, who then found out the pursuit had continued, ordered all units to abandon the chase.

But because it was not given across all three radio channels, some police units did not get the message.

One officer, who was on a motorcycle, did not hear the order and started chasing Batt.

During this chase, Batt reached a speed of about 120kmh in a 50kmh zone, and crashed.

The authority made seven recommendations, including that police review and amend their fleeing driver policy and air operations policy.

Radio protocols and the role and responsibilities of the helicopter also needed revising, it said.

The authority also said police needed to clarify their policy on using road blocks and closures, and ensure it was taught properly in officer training.

Assistant Commissioner Upper North Allan Boreham said police accepted the shortcomings of the chase and the policy would be amended.

- © Fairfax NZ News