Sarah Atangana was deported to the US this week after being detained in Villawood after the completion of her prison sentence. She said she had been attacked twice in three months inside.
Several detainees have told Guardian Australia that a woman was held down and physically and sexually assaulted by a group of detainees in July after they entered her room early in the morning.
Others said they had been left with permanent scars after being assaulted in Villawood.
Guardian Australia has seen photos of a man who suffered severe burns to 12% of his body after a detainee poured a vacuum flask of coffee over him earlier this year. The matter was referred to the Australian federal police but no further action was taken.
Yongah Hill is regarded by sources with knowledge of the detention regime as one of the most dangerous and consistently violent.
A Turkish national, 32-year-old Gokhan Can, was stabbed to death as he slept in his room at Yongah Hill in June. A riot broke out in the centre days later.
A refugee held at the centre said it was overcrowded, unsafe and filled with people who had been detained indefinitely for years.
The average period of detention in Canada is 24 days. In the UK it is 29 and in the US 43.
About 1,500 people are currently in immigration detention centres across Australia. The cohort is dominated by the so-called 501s (892 people), with 251 asylum seekers and 369 overstayers or people whose visas had been cancelled for other reasons.
The Al Kateb judgment by the high court in 2004 found that indefinite detention without trial or charge was lawful.
An ABF spokesperson acknowledged there had been recent cases of assaults by detainees against other detainees and staff at immigration detention facilities.
