Aboriginal and Torres Strait Islander readers are advised that this article contains the name of an Indigenous person who has died.
Two Aboriginal people have died in custody in the ACT in less than one week.
On Tuesday the ABC reported Howard Hall, 38, died at the Alexander Maconochie Centre after suffering a "medical episode", with the national broadcaster reporting they had received permission to name Mr Hall.
His death comes after the ACT Corrective Services had confirmed a 73-year-old Aboriginal man died in the same facility on Thursday last week while on remand.
Chief executive of the Aboriginal Legal Service (ALS) NSW/ACT Karly Warner said the organisation was devastated by the passing of the two men.
"The impacts of these individuals' deaths will be felt not only by their immediate families, but throughout their communities," Ms Warner said on Tuesday.
It was reported emergency services had been called to the prison at 2.40am on Monday, following reports Mr Hall needed medical treatment. He died at the scene despite "significant efforts" by paramedics, an ACT policing spokesperson said.
Winnunga Nimmityjah Aboriginal Health & Community Services chief executive Julie Tongs told the ABC a Royal Commission into First Nations deaths in custody at the Alexander Maconochie Centre was needed.
"It always falls on deaf ears," Ms Tongs, whose organisation counted Mr Hall as one of their clients, said.
"I'm not sure why there's so much resistance. And until the government acknowledges that there's a problem, we're never going to change anything."
There have been at least 587 Aboriginal and/or Torres Strait Islander deaths in custody since the 1991 Royal Commission into Indigenous deaths in custody.
Data from the Productivity Commission released last month revealed Indigenous people in the ACT are incarcerated more than 21 times the rate of non-Indigenous people.
In 2014, the discrepancy rate was less than 12 times.
Ms Warner said the fact more than 30 years on from the landmark royal commission, Indigenous people keep dying in custody, was simply "unacceptable".
"The ACT government must do more to address its shameful over-imprisonment of Aboriginal people," she said.
She argued it was known police and courts were the "gateway to prison," with Indigenous people facing "worse outcomes at every stage of the criminal process".
To meet its obligation under the closing the gap agreement, Ms Warner said the ACT Government needed to take "urgent action" to address the drivers of mass incarceration: over-policing and over-criminalisation.
The government needs to invest in evidence-based, community-led solutions, as well as the priorities agreed upon in the National Justice Policy Partnership, Ms Warner added.
