The Independent Police Conduct Authority has found that the actions of two officers during a pursuit in which a woman suffered life-threatening injuries amounted to misconduct.
In December 2008 the constables, referred to as A and B, chased teenaged driver Thomas Hancy after he failed to stop in central Christchurch.
Hancy ran a red light, crashing into Laura Henry, who spent two-and-a-half months in hospital and has not fully recovered from her injuries.
Two of her passengers, including a five-year-old child, were also injured.
The authority said the pursuit covered almost 2km in one minute, with Hancy's stolen Subaru Impreza averaging 108km in a 50km zone.
The authority said the officers did not properly consider the risks and should have stopped the pursuit earlier. It said the officers communicated inadequately with Southern police communications, and breached policies and procedures.
District commander Superintendent Dave Cliff says disciplinary action has been taken against the officers, but cannot reveal what this is. The officers remain with the Christchurch police force.
Superintendent Cliff says both officers made serious mistakes and are shocked at what happened, but their intention was to stop Hancy before he hit someone.
Hancy was jailed for four years and three months after pleading guilty to aggravated wounding, two charges of reckless driving causing injury, driving while disqualified, unlawfully taking a motor vehicle and failing to stop.