A tribunal has accepted an asylum seeker's claims that he was forced to take part in fights at the troubled Mt Eden prison in Auckland.
The man said he had been beaten during his two-month detention before he was allowed to move to the Mangere refugee resettlement centre.
He told the immigration and protection tribunal he felt "psychologically ill" during his stay at Mt Eden.
"Some inmates were members of the Black Power and Mongrel Mob [gangs] and carried knives," the tribunal was told.
"They would take the appellant into a room with some five to 10 persons and he would be forced to fight someone bigger than himself.
"The guards were not aware of what was going on, and he did not inform them as he feared being characterised as an informer."
Read the tribunal's decision here.
The tribunal, which heard his appeal for refugee status, accepted his evidence about the violence he suffered.
It said: "He had been beaten by gang members and been forced into gang fights against persons stronger than himself on a weekly basis.
"He stated that he still had light scarring on his head from injuries he had incurred.
"Despite the fact that no contemporaneous psychological or medical evidence have been produced concerning the effects of this mistreatment on the appellant at this time, or any report or correspondence from Immigration New Zealand's compliance branch tendered on the matter, the Tribunal accepts the appellant's evidence that he was the victim of physical violence and forced to fight in gang fights during his period in prison."
The man claimed refugee status when he arrived in New Zealand in 2014 from Somalia, and he was immediately taken to Mt Eden prison.
He claimed he been kidnapped and ill-treated by Al-Shabaab, a militant Islamist group in Mogadishu, who attempted to forcibly recruit him as a jihadist.
The man said the group later killed his father, brother and a close friend when he refused to join them, and that he feared for his life.
He said the violence he suffered at Mt Eden prison had put him under mental pressure which meant there were differences between his initial claim made then to Immigration New Zealand and his subsequent evidence to immigration officials and the tribunal.
But the tribunal said while it allowed for the effects the abuse could have had on the man's mental and physical health, the violence did not answer the tribunal's concerns about the discrepancies and implausibility of the man's version of events in Somalia.
The man's Auckland-based lawyer, Tonderai Mukusha, said his client did not want to comment while he awaited a High Court decision on his refugee appeal.
A separate inquiry into Mt Eden prison, managed at the time by private operator Serco, is due to report its findings soon.