Authorities have launched an investigation into the death of an Iraqi detainee at the Villawood detention centre in Sydney's west.
Advocates said the 28-year-old refugee was held at the centre for the past five years and was found dead at the facility in a suspected suicide on Sunday morning.
The Department of Home Affairs and Australian Border Force confirmed the death and said the incident would be probed.
"The Department and Australian Border Force express our condolences to the man's family and friends," a department spokesperson said in a statement.
"The matter has been referred for investigation to the appropriate agencies, including the NSW Coroner.
"As this matter will be subject to ongoing investigation, it would not be appropriate to comment further."
The Refugee Action Coalition (RAC) said the detainee had requested to be moved from a compound at the facility multiple times due to "tensions with other detainees".
RAC spokesperson Ian Rintoul said the man was involved in a fight with another detainee on Saturday and his room was last checked at about 10pm last night.
"Those requests [to be moved] had been ignored," he said.
"We know that there's plenty of room inside Villawood, there's no reason why he shouldn't be moved."
Mr Rintoul said it was "beyond belief" such incidents were still taking place at immigration detention facilities and called for them to be shut down.
"This [incident] in particular has caused an enormous amount of distress inside Villawood," he said.
"Detention centres have long been understood to be factories of mental illness … it [Villawood] should be closed."
The ABC understands mental health care is provided to detainees by GPs, psychologists, and counsellors on a visiting basis, or through the use of telehealth facilities.
