A New Zealand national claims his head was smashed into a glass window by Perth prison guards while he was detained without charge for several months for links to a motorcycle gang.
Ko Haapu, who was detained in Casuarina maximum security prison after his visa was revoked, says he still had the scars on his face from the assault.
"They would just keep pushing and pushing and trying to get us to break, so when I started refusing to be part of their system as a prisoner, my wrists were locked and my head was smashed into the glass windows," Mr Haapu told Radio New Zealand on Thursday.
"They made sure to lock my door and push everyone out of those rooms before they let me out so there were no witnesses there."
Mr Haapu's detention drew fire from across the ditch in early November when New Zealand Maori Party co-leader Marama Fox suggested the 34-year-old's imprisonment was a breach of human rights.