The Royal Commission into children in detention in the Northern Territory says the financial costs are "staggering" and its final report to be released on Friday will show the problem is "deep seated, confronting and come at an enormous human and financial cost".

Commissioners Mick Gooda and Margaret White said their report would show that the Northern Territory and Commonwealth governments were right to call the inquiry, which was sparked by the ABC's Four Corners program Australia's Shame broadcast in July last year.

The program showed young males being strapped to mechanical chairs and tear-gassed at the Don Dale Youth Detention Centre in Darwin.

One of those was 17-year old Dylan Voller who was handcuffed, hooded and strapped to a restraint chair for almost two hours.

Mr Voller is one of the 24 "vulnerable witnesses" who have testified before the commission, which heard from a total 214 witnesses and received 480 witness statements.

The commissioners also toured the Don Dale facility as part of their work.

In establishing the Royal Commission, Prime Minister Malcolm Turnbull described the scenes of young people being restrained as "deeply shocking".

In an opinion piece published Friday, the commissioners said their 15-month investigation had uncovered disturbing evidence.

"What we have found is disturbing on many levels, not least of course because it has occurred on our watch and in our country," the commissioners wrote on Friday. "The financial costs are also staggering."

The statistics paint a bleak picture for indigenous Australia with figures showing Aboriginal children are disproportionately in out-of-home care and detention.

Of the 1,020 children and young people in out-of-care home in the NT in June 2016, 89 per cent were Aboriginal.

And of the 20,465 notifications received by Territory Families, 78 per cent related to Aboriginal children and young people.

While 30 per cent of the Northern Territory population are Aboriginal, 94 per cent of the adult and youth detention population is indigenous.

The rate of young people receiving child protection services in Australia is 28.6 per 1,000 nationally but 91.5 per 1,000 in the NT.

"The problems we have identified are deep seated, confronting and come at an enormous human and financial cost," the commissioners said. "Neither will be sustainable for the NT in the short term."

The Royal Commission was originally given seven months to complete its report but ended up taking more than double the time because it needed to investigate the child protection system alongside youth detention.

The report will recommend changes to the youth detention system that it says Deloitte estimates could save $335.5 million by 2027.

'Great appetite for change'

In a speech in September, Mr Gooda said people had become "cynical and fatigued" by the 50 prior reports detailing the extreme disadvantage blighting indigenous Australia, that had not led to any meaningful change.

But he said that he sensed a great appetite within Aboriginal communities to cease blaming governments and start solving their problems themselves.

"When we had a meeting with the full Councils of the Northern Land Council and the Central Land Council...half of our time was taken up by communities getting up and saying we've got to stop blaming government, we've got to start taking responsibility for what we have contributed to as parents," he told the NT Council of Social Service.

"That tells me that there is a great appetite within the Aboriginal community for change and to take responsibility," he said.

He said the report would recommend a plan that, if implemented, would deliver "widespread reform" for indigenous families.

Detention system broken

The Royal Commission's interim report released in March said it was too early to make recommendations but it had heard youth detention centres were "harsh, bleak and not in keeping with modern standards".

A recent speech by Mr Gooda suggests the Royal Commission is likely to recommend sweeping changes to youth justice in the NT.

It is likely to call for an end to "punitive" incarceration for "the small number of children who will need to be kept in detention" and focus on changing the way police respond to reports of young people committing crimes.

Mr Gooda has said detaining young people in centres like Don Dale does lead to rehabilitation but it also leads to recidivism and it showed the youth prison system was broken.

Police are likely to be encouraged to avoid heavy-handed custodial options for youths and instead focus on rehabilitation options, a model followed by police in New Zealand.

"That doesn't mean a go easy approach - what it does mean though is recognising that the chance is there at an early stage to change the course of a young person's life for good," Mr Gooda said.

Follow Latika Bourke on Facebook