The young man left with a broken neck after apparently being hit by a police baton while officers were unlawfully trying to close down a Wellington party will fight for compensation.
Four years after the incident, no officer has been held responsible for the injury, which was close to leaving Jakob Christie in a wheelchair.
Mr Christie's lawyer, Keith Jefferies said they would start negotiating with police for a "significant" amount of money to compensate for ongoing physical and psychological harm.
"The doctor said he could have been paralysed - it's affected his confidence and he's been depressed from time to time."
A report by the Independent Police Conduct Authority (IPCA) into complaints against officer conduct at the Khandallah property in September 2009, slammed police behaviour and criticised the length of time it had taken for police to complete an internal investigation.
Police say even though their own inquiry cleared officers of wrong-doing, they accepted the watchdog's report and the "possibility" Mr Christie's injury was caused by a police baton.
Mr Christie was left in a neck brace and on painkillers for three months after apparently being struck from behind by a Tactical Policing Unit officer's baton.
The 23-year-old, who was 19 at the time, said police were called when gatecrashers would not leave.
By the time officers arrived the uninvited guests had left, but police forced the others out of the house.
IPCA chairman Sir David Carruthers said on the balance of probabilities, Mr Christie, suffered a broken neck when he was hit with a baton by a member of the Tactical Policing Unit.
The report was not able to identify the responsible officer but Mr Christie said even though time had passed, he could probably identify the person responsible.
"I still believe if all 11 officers were lined up I could probably pick him out. I still can picture his facial expression."
Mr Christie asked for photos of the officers in the days immediately following the incident, but he was denied the request.
Assistant Commissioner Grant Nicholls said they accepted the possibility that the injury Mr Christie suffered on that night "may well have been caused by a police baton. That is a possibility".
Asked if police would apologise, Mr Nicholls said those discussions would not be held in public.
He said the IPCA had made its findings on the balance of probabilities, which was a lower threshold than the high standard of beyond reasonable doubt.
Mr Nicholls said police had investigated on the basis of bringing a criminal prosecution. However, the investigation did not find sufficient evidence to charge an identified person.
Mr Nicholls stressed the situation at the party had been complex.
"If we have a look at what was going on that night, there were 60 to 100 young people in that house and a three-foot-wide hallway. Midnight, alcohol flowing, bottles, violence had occurred - that was the original call."
He said police acted unlawfully in entering the house, but had "acted with the best intent" in misinterpreting the law.