A young man beaten with batons and pepper-sprayed 65 times by four police officers in a closed cell has received $30,000 in compensation.

Rawiri Falwasser, 26 at the time, was seriously injured while in custody at the Whakatane police station after he was arrested on suspicion of stealing a car on Labour Day 2006.

Sergeant Keith Parsons, Sergeant Erle Busby, Senior Constable Bruce Laing and Constable John Mills were later found not guilty of nine charges of assault by a jury in June 2008.

But Justice Lyn Stevens has ruled in the High Court at Auckland that Mr Falwasser should be paid $30,000 in damages under a breach of the New Zealand Bill of Rights Act.

Justice Stevens said there was no dispute that Mr Falwasser was assaulted several times with police batons - splitting his head with a 6cm cut - and repeatedly pepper-sprayed over a 20-minute period.

In his decision, he said the New Zealand Police admitted that the use of baton blows and pepper spray was an abuse of power and did not submit justified use of force as a defence.

The incident was captured on closed-circuit security cameras, and Justice Stevens said the actions ofthe four senior officers were unnecessary, unjustified and without lawful authority.

Rawiri Falwasser was arrested on Labour Day 2006 on suspicion of stealing a neighbour's car. He had not been in trouble with police before and was later diagnosed as having a psychotic episode, despite having no history of mental illness.

He resisted requests to fingerprint and photograph him - but was not violent - and was struck with a baton after again refusing to leave the perspex holding cell.

A 20-minute assault followed in which Mr Falwasser was struck several times with batons and was pepper-sprayed 65 times.

The spray was squirted through vents at the top and bottom of the cell, and there was so much in the air that other police officers had to leave the room. The doctor called to treat Mr Falwasser could not see him through the fog of spray.

In his evidence, Mr Falwasser said he thought he would suffocate and die and he was in terrible pain.

"He described the pain as feeling like really hot water being poured over your body but without any physical burn," said Justice Stevens.

A psychological report written last August, said Mr Falwasser had been diagnosed with post traumatic stress disorder. He was unable to sleep, had nightmares, felt isolated from friends and family and had not lived independently since the incident.

The four officers were charged with nine counts of assault but were acquitted at the Tauranga District Court.

Internal disciplinary charges were also laid and Mr Parsons resigned from the police before the tribunal hearing. Mr Mills and Mr Busby were transferred from Whakatane, and Mr Busby was demoted in rank from sergeant to senior constable.

Mr Laing was found guilty of two breaches of police rules but resigned before any penalty was imposed.

In submissions to the court on behalf of Mr Falwasser, Rodney Harrison, QC, said the most excessive and shocking aspect of the incident was the repeated use of pepper spray - particularly after Mr Falwasser suffered the head injury.

Justice Stevens ruled there was a serious breach of one section of the Bill of Rights Act, which states that everyone deprived of liberty shall be treated with humanity and respect. But he ruled against a second claimed breach of the Bill of Rights relating to torture, cruel, degrading or disproportionate treatment or punishment.

"The conduct of the police officers during the incident, while serious and wholly unacceptable, does not in my opinion reach that standard," said Justice Stevens.

"Mr Falwasser was, despite his lack of compliance and intransigence, entitled to be treated during that 20- minute period of the incident with humanity and with the respect of the inherent dignity of the person. He was not."

His father, Charley Falwasser, told the Weekend Herald the High Court decision was another step to getting closure.

Mr Falwasser said Rawiri, now almost 30, still had post traumatic stress disorder but was looking for work.

"We feel vindicated that in the High Court there was an acknowledgement that an assault - totally unnecessary - occurred."