Australia must join other countries around the world in "radically rethinking" its dependence on prisons and start having a serious conversation about the over-incarceration of Aboriginal people for "petty offences", a US-based prison reform activist has warned.

Baz Dreisinger, the author of Incarceration Nations: A Journey to Justice in Prisons Around the World, told an audience gathered at Melbourne Law School on Monday night there was growing public awareness of the mass incarceration "crisis" and its economic failings, but a deeper discussion must be had about the "fundamental immorality" and "systemic racism" underpinning criminal justice systems across the globe.

"The conversation is on everyone's lips," Dr Dreisinger told the packed theatre at Melbourne University.

"There are more African-Americans under federal supervision in the US today then there were slaves at the height of slavery.

"[The prison industry is] a billion-dollar industry; depending the state, we are spending at least 10 times more on incarcerating people than on educating them."

Crucially, there had been sustained debate over the past few years, she said, about how mass incarceration — which disproportionately impacted racial minority groups — was a new way of "creating racial segregation" in the US.

But until recently, she argued, the US had been "having this conversation in a vacuum" and failing to consider its "role in exporting this model to the rest of the world".

"Almost every country has its 'other' [group that is over-represented in the justice system], and has over-incarcerated that other group in almost identical ways — that is by criminalising them, usually through the use of petty offences," said Dr Dreisinger, who is also an English professor at John Jay College of Criminal Justice in New York.

"And to see that played out again and again in one way or another is a painful thing to witness."

In Australia, that "other" is Aboriginal and Torres Strait Islander people, who make up just 2 per cent of the broader Australian population but more than a quarter of the nation's prison population. And while the total number of prisoners in Australia has skyrocketed over the past decade, much of that growth is a result of higher rates of incarceration of Aboriginal people, particularly women, who are more likely than non-Indigenous women to be arrested for public order offences and other minor crimes.

There is debate in the US that disproportionate imprisonment of minority groups is a new form of racial segregation, Dr Dreisinger says. ( ABC: Alkira Reinfrank )

'Australia thinks of itself as noble'

Roxanne Moore, the national secretariat for the Change the Record campaign and one of four Australian experts who took part in a panel discussion after Dr Dreisinger's lecture, said the first step in addressing the over-representation of First Nations Australians in prison was acknowledging the "systemic racism" within the justice system.

"Australia, I think, thinks of itself as this noble, civilised place but we're literally torturing Aboriginal kids in prison," Ms Moore said, referring to revelations in 2016 of the shocking mistreatment of children in Darwin's Don Dale detention centre.

More than 400 Aboriginal people have died in custody since the royal commission into Aboriginal deaths in custody in 1991, she added, which recommended, among other sweeping reforms, that the crime of public drunkenness be abolished.

Those 400 include Yorta Yorta woman Tanya Day, who died in a Castlemaine police cell in 2017 after being detained for public drunkenness, sparking a coronial inquest into her death.

On Tuesday, Ms Day's family would appear at an inquiry hearing, Ms Moore said, to urge the coroner to investigate the role of "systemic racism" in her case — for instance in the responses of police and ambulance officers who interacted with her in her final hours.

"In Australia, the system isn't broken — it does exactly what it was set up to do," Ms Moore said.

"If we are to end some of these injustices we have to dismantle … capitalism, racism and all these colonial structures that we have … rather than tinkering around the edges with reformist work."

This, she argued, meant empowering Aboriginal people to "make decisions about our own lives".

"It means getting control back to our communities and community-controlled organisations, it means we're running the services and supports that we know we can deliver," she said.

'Tear down prison walls'

The over-incarceration of First Nations Australians is also set to become an election issue, with Labor promising $107 million to tackle the crisis through funding boosts for Aboriginal legal services and justice reinvestment programs, if it is elected.

Announcing the package last week, senator Patrick Dodson and shadow attorney-general Mark Dreyfus said a Labor government would also pursue justice targets under the Closing the Gap framework and invest in family violence prevention programs.

"If we properly fund First Nations-led legal services, show leadership with nationally coordinated targets, and invest in what works, we can close the justice gap," Senator Dodson and Mr Dreyfus said.

"Labor will uphold the principle that imprisonment should be an option of last resort."

The prison industry is a fundamental failure, according to Sisters Inside founder Debbie Kilroy. ( ABC News )

But Debbie Kilroy, chief executive of Sisters Inside and a panellist at the Melbourne Law School event, said the most effective way to reduce the number of people in custody was to stop building more prisons and "start thinking outside the bars".

"We've actually got to … tear down the prison walls, address the racial capitalism in this world and start [investing in] social supports in our community so that everyone does have access to health, housing, education and employment if they choose to do so," said Ms Kilroy, who has worked with criminalised and imprisoned women in Queensland for almost three decades.

"We continue to pour buckets of money … into a prison industry that is a fundamental failure," she added, perhaps in reference to the alarmingly high rates of recidivism around the country.

In February, for instance, the Queensland Productivity Commission released the draft report for its Inquiry into Imprisonment and Recidivism, which found that, although crime rates were down, rates of imprisonment were increasing, especially those of Aboriginal women. Meanwhile, the proportion of prisoners returning to prison with a new sentence within two years of release soared from 29 per cent in 2007 to 40 per cent in 2017.

But even though crime rates were declining, Ms Kilroy said, governments were criminalising a broader range of behaviours — including rough sleeping, begging, and public drunkenness — many of which disproportionately affected those living in poverty.

"The time has come when we have to distribute wealth [more evenly]. We have enough wealth in this country to ensure no person is homeless, but we actually accept that," she said.

"I put a challenge out to those of you that are [studying] law or who are lawyers: how are you using that privilege?" Ms Kilroy asked the crowd who, she said, were sitting "in one of the most prestigious universities in the country".

"You have something not many people will have in their lives, which is a law degree and … the power to walk into a court room and be heard."