The men were assaulted in two separate cells in the north accommodation unit about 11.35am on August 7.

Both were taken to Canberra Hospital. One was treated and returned to the jail the same day while the other was admitted to hospital and returned the next evening.

A Justice and Community Services spokeswoman said the error was regrettable and an Aboriginal case manager had since been helping the inmates keep in contact with their family.

"When an incident occurs, ACT Corrective Services' immediate priority is to ensure the safety and security of individual detainees and the Alexander Maconochie Centre," she said.

"Notifications to next of kin are required to be made in a timely manner. Regrettably on this occasion the appropriate notification did not occur in line with prescribed policy.

"This has been addressed as part of an internal review of the incident and all correctional officers have been reminded of their responsibilities."

ACT Policing said they were alerted to the assaults about 3.30pm on August 7.

A spokeswoman did not answer questions about whether police had interviewed or charged anyone in relation to the bashing, nor whether they had viewed any CCTV, but said their investigation was ongoing.

JACS would not detail what injuries the men sustained nor what aftercare was being provided, citing the ongoing police investigation and privacy laws.

Winnunga Nimmityjah chief executive Julie Tongs said it was unacceptable no one had been charged, three weeks after the attack.

"Regardless of whether you're on the inside or outside, you should be charged if you assault someone," Ms Tongs said.

Ms Tongs said the bashing and later death of Steven Freeman appeared to have changed little in the prison.

"It's like here we go again," Ms Tongs said.

Do you know more? Email katie.burgess@fairfaxmedia.com.au