Police did not investigate the man's complaint accusing police of assault two months earlier. (file image) Photo: RNZ
Police have been heavily criticised for using "excessive force" against a detained man.
The Independent Police Conduct Authority investigated an altercation at Counties Manukau Custody Unit in August 2021, when the man was being transferred from prison for a court hearing.
Chair Judge Colin Doherty said there were two "disappointing" police "failures" and "clear CCTV evidence".
Police punched and kicked the man excessively but "seemingly excused" it, Doherty said.
Two months earlier, the man had laid a complaint accusing police of assault, but police did not investigate.
The August altercation could have been avoided if the complaint was taken seriously, because the man was aggravated by the poor response to his allegations, the IPCA said.
"It is entirely reasonable to conclude that had the detainee's earlier complaint been adequately dealt with, this later incident would not have occurred," Doherty said.
In a statement, Counties Manukau police acting district commander inspector Matt Srhoj said the man seriously assaulted an officer in the incident in August 2021, when police used force restraining him.
The officer was concussed.
Police accepted the findings and have begun an employment investigation.
"We are in the process of making improvements to the complaints process," Srhoj said.