A pending inquest into Mr Freeman's death also appears to be closely focussed on why Mr Freeman, not a known heroin user upon admission, was able to access the methadone program from April.

It is also taking expert evidence on the impacts of opioid toxicity, an avenue suggesting high levels of an opioid drug were found in his system.

Mr Freeman was found dead in his cell in the Alexander Maconochie Centre in late May, roughly a year after the remandee was placed with sentenced prisoners and almost immediately subjected to a near-fatal bashing.

The cause of his death has so far not been made public, although the results of an autopsy have been returned.

But a list of issues to be explored by the coronial inquest, seen by Fairfax Media, clearly shows that the methadone program, the effect of opioid toxicity, and the observation and supervision of Mr Freeman will be considered closely.

Winnunga Nimmityjah Aboriginal Health Service called on Thursday for the newly-announced royal commission to be broadened to look at cases like Mr Freeman's.

Chief executive officer Julie Tongs says there is a strong link between the shocking treatment of juvenile detainees in the Northern Territory and what is happening to other Indigenous inmates, including adults, across the country.

Ms Tongs called on Prime Minister Malcolm Turnbull to ensure the royal commission had a national focus - something the Coalition has at this stage ruled out.

"Given the treatment of Aboriginal prisoners, where our young men and women are going straight from a life-threatening juvenile system to a life-threatening adult system throughout the country, we need a national response," Ms Tongs said.

"We can't wait, and we can't rely on the good will of any future government, or worse, the leaking of more of what WA Liberal Ken Wyatt called Abu Ghraib-like video to make the broader community sit up and take notice," she said.

The coronial inquest is one of two probes currently underway. The second is being overseen by independent expert Philip Moss, a former integrity commissioner who produced a damning report about abuse inside the Nauru detention centre.

After Mr Freeman's bashing, he was returned to jail after prison authorities promised he would be kept safe.

Extensive measures were to be put in place to ensure he wasn't able to be harmed or harm himself.

Ms Tongs previously wrote to Mr Moss and asked him to look into the "deeply flawed" advice from prison authorities last year that prison was the safest place for Mr Freeman.

The inquest will also look at Mr Freeman's designation as a "prisoner at-risk", what that meant, and how it was dealt with.