Advocates have called for greater investment in prison support services as more self-harm claims surface at Acacia Prison.

The alleged incidents follow the Sunday afternoon riot at Acacia involving about 100 prisoners.

National Suicide Prevention and Trauma Recovery Project spokeswoman Megan Krakouer said she had been told of six self-harm incidents on Tuesday and two on Wednesday.

"Of the six (on Tuesday) I was advised two people were hospitalised," she said.

"Five of the six people were Indigenous.

"There are people sleeping in damaged cells, with broken windows and broken objects, which makes self-harm more likely, and some sleeping on the floor with no mattresses or bedding."

A Department of Justice spokesperson said four prisoners from one block at the privately-run prison had been placed under observation after receiving treatment for minor injuries on Tuesday.

"Acacia has ordered additional patrols and the medical team is assessing the most vulnerable prisoners to identify ongoing needs and support," they said.

The Department of Justice spokesperson said Acacia remained on a "modified regime" following Sunday's riot and "significant damage" to infrastructure had been recorded.

Ms Krakouer said the prison system lacked psychological support services.

"Restorative justice and rehabilitation is a myth right now," she said.

"Our people are in pain and there are so many vulnerable people, and their families have no knowledge of what is happening to their loved ones."

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