Comcare, the federal work health and safety authority, charged the federal government department and its refugee healthcare provider on March 3 with breaching work health and safety laws.

The charges state each defendant failed to comply with its health and safety duty, and exposed the detainee to a risk of death in early 2019.

Iraqi man Milad Abdulrahim Aljaberi, 26, took his own life inside Sydney's Villawood detention centre on March 4, 2019.

The case was mentioned for the first time in Downing Centre Local Court on Tuesday

"These are serious matters," magistrate Jennifer Atkinson said.

A lawyer for Home Affairs said it was "premature" to suggest it could enter a plea to the charges by the next court date on August 17.

More than 600 documents were expected to be served on the defendants, in addition to a bulky brief of evidence, the court was told.

"We don't even have a statement of facts, Your Honour," Tim Game SC said.

"We were charged at the last minute of the last day of the notification period."

Four experts are due to be called by Comcare if the matter is set down for hearing.

"If this runs to hearing, I imagine this will run for days, if not weeks," Ms Atkinson said.

Home Affairs and International Health and Medical Services each face two category two offences under work health and safety laws.

Each charge carries a maximum fine of $1.5 million.

The defendants are accused of failing to maintain their duty to not place detainees' health and safety at risk, as far as reasonably practicable.

The detention centre allegedly lacked sufficiently skilled mental health clinicians, an "on-call" psychiatric consultation and adequate staffing on weekends.

Home Affairs and IHMS are also accused of failing to provide adequate supervision of mental health nurses on weekends, including when the nurses changed monitoring of at-risk detainees.

IHMS is a wholly owned subsidiary of Singapore-based healthcare provider International SOS.

It has received $2.06 billion since 2009 to provide health services in Australia's detention centres.

The Asylum Seeker Resource Centre said people held in detention centres were supposed to receive a standard of health care commensurate with that available in the community.

"However, we see large gaps and an intransigent lack of accountability for closing these gaps," Carolyn Graydon, ASRC's Human Rights Law Program manager, said in a statement.

"We are deeply disturbed about the continuing poor standards of both mental and physical health care received by our clients in immigration detention centres, including those held in North West Point on Christmas Island where the extreme isolation adds to people's mental distress."

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Australian Associated Press