Mr Kingi failed to stop when the police vehicle's lights were turned on.
The officer followed, accelerating to about 80km/h, but did not use his siren, as required on urgent duty driving.
At 9.45pm the officer formally commenced pursuit, activating his siren and notifying police central communications.
The police dispatcher mistakenly noted that the pursuit was taking place in a 100km/h zone, rather than a 50km/h zone, and later also misheard the name of the street.
At 9.46pm the dispatcher asked for an update and was told the fleeing car's speed was about 130km/h, and the officer's 120km/h.
When asked the reason for the pursuit the officer said it was "just a routine stop''.
The authority said this was inadequate, and the officer should have given a specific reason, such as excessive speed.
Shortly afterwards the officer lost sight of the fleeing car after mistakenly turning to follow the wrong vehicle.
But he didn't follow policy for abandoning a pursuit, which requires officers to stop, turning off lights and sirens and inform police communications.
He then began a search phase without express instructions from the pursuit controller, as required by policy.
The officer continued looking for the fleeing vehicle, and found the crash scene on Nelson Rd.
A crash investigation found the Mitsubishi had slid off the road after taking a right-hand corner at between 130km/h and 136km/h.
Mr Kingi, who had four drink-driving convictions, was found to have more than double the blood alcohol limit.
The three deceased had died at the scene, while Ms Badger had been able to climb out of the vehicle.
The authority concluded the officer was correct in starting the pursuit, which covered 2.5km in 1.5 minutes.
However the officer's speed of 127km/h in a 50km/h zone was not justified, and the pursuit should have been abandoned earlier.
It recommended both the officer and dispatcher be re-trained on police driving policy.
The authority also recommended police implement hands-free radio technology in all operational vehicles.
It said all officers involved in critical incidents be drug and alcohol tested, although there was no evidence the pursuing officer had used drugs or alcohol.
Eastern District Commander Superintendent Sam Hoyle said Gisborne police staff had undertaken refresher driver training following the IPCA report.
He said police accepted the authority's findings and had already reinforced to staff police policy around fleeing drivers.
"The officer involved in the incident has undergone remedial training and has been recertified as a `gold' licensed driver under the Professional Police Driving Programme (PPDP).
"A PPDP panel has reviewed the officer's actions during this incident and reminded him of his responsibilities under the police urgent duty driving and fleeing driver policies.
"He is well aware now of his responsibilities should such an event occur again,'' Mr Hoyle said.
All staff would be "extra vigilant'' in any future pursuits they undertake, he said.
"We will continue to review every crash where a fleeing driver has been involved as per our protocols.''
Mr Hoyle said communications centres were also reviewing their practices for handing control of fleeing driver incidents from one supervisor to another.
"The dispatcher involved in this incident has undergone refresher training in the requirements of the fleeing driver policy, and the pursuit controller has been reminded of the policy's abandonment procedures.''
