The high security unit of Darwin's Don Dale youth detention centre should be shut immediately and there should be a plan for closing the entire centre within three months, an inquiry has recommended.

Key points: The investigation found "shocking and systemic failures occurred over many years and were known and ignored at the highest levels"

The investigation found "shocking and systemic failures occurred over many years and were known and ignored at the highest levels" Prime Minister Malcolm Turnbull said the Government "will now carefully consider those findings directed to the Commonwealth"

Prime Minister Malcolm Turnbull said the Government "will now carefully consider those findings directed to the Commonwealth" Chief Minister Michael Gunner apologised for the failings of successive NT governments

The Royal Commission into the Protection and Detention of Children in the Northern Territory also called for the age of criminal responsibility to be raised from 10 to 12.

The $54 million inquiry, which was prompted by ABC's Four Corners report on the Don Dale Youth Detention Centre, investigated conditions in the NT's detention centres.

The program highlighted the treatment of Dylan Voller, who was shown hooded in a restraint chair while in detention.

NT Chief Minister Michael Gunner apologised for the failings of successive NT governments, calling it "a stain on the NT's reputation" and announced a comprehensive overhaul of the youth justice and child protection systems.

Some of the key recommendations from the inquiry include:

Only allowing children aged under 14 to be detained for serious crimes

Only allowing children aged under 14 to be detained for serious crimes Banning the use of tear gas and force or restraint being used to discipline children

Banning the use of tear gas and force or restraint being used to discipline children Introducing body-worn video cameras in youth detention centres

Introducing body-worn video cameras in youth detention centres Prohibiting extendable periods in isolation over 24 hours, or its use as a punishment

Prohibiting extendable periods in isolation over 24 hours, or its use as a punishment Requiring youth justice officers to have demonstrated experience in working with youth

Requiring youth justice officers to have demonstrated experience in working with youth Developing a 10-year generational strategy to address child protection and prevention of harm to children

Developing a 10-year generational strategy to address child protection and prevention of harm to children Increasing engagement with and involvement of Aboriginal Organisations in child protection, youth justice and detention

"We recognise some of what we are proposing marks a profound shift from past practice in the NT, but it is necessary as what has been relied upon to date has and continues to simply fail the entire community," co-commissioners Margaret White and Mick Gooda said in a statement.

They said their investigation had found "shocking and systemic failures occurred over many years and were known and ignored at the highest levels".

"Children and young people were subjected to regular, repeated and distressing mistreatment in detention and there was a failure to follow the procedures and requirements of the law in many instances," they added.

They said the NT's detention system "failed to comply with basic binding human rights standards in the treatment of children and young people" and that children were denied their basic needs such as water while imprisoned.

The commissioners said their findings vindicated the decision of the Australian and NT governments to call for the royal commission.

"These things happened on our watch, in our country, to our children," they said.

"The time for tinkering around the edges and ignoring the conclusions of the myriad of inquiries that have already been conducted must come to an end."

Dylan Voller was hooded and strapped to a chair while a youth detainee. ( Supplied )

System must break 'inevitable cycle' of care and detention

The system needs to undergo a fundamental change to break the "seemingly inevitable cycle" rotating children from care into detention, the commissioners said.

"Perpetuating a failed system that hardens young people, does not reduce reoffending and fails to rehabilitate young lives and set them on a new course, is a step backwards," they said.

"The failures we have identified have cost children and families greatly, they have not made communities safer and they are shocking."

The royal commission's findings reaffirmed much of the evidence heard during the course of the inquiry, including that the NT's youth detention centres were not fit for accommodating - "let alone rehabilitating" - children and young people.

It also found that children were subject to verbal abuse, physical control and humiliation, including being denied access to basic human needs such as water, food and the use of toilets.

Children were also dared or bribed to carry out degrading and humiliating acts, or to commit acts of violence on one other.

They also found that youth justice officers restrained children using force to their head and neck areas and that isolation has continued to be used inappropriately, punitively and inconsistently with the Youth Justice Act (NT), causing many to suffer.

Call to end detention of children aged under 14

In child protection, the commission found that the NT Government had failed to comply with the statutory requirements that all children in out-of-home care have timely care plans, and found there was a major shortage of available foster and Aboriginal kinship care placements.

The commissioners called for a greater use of youth diversion, and an end to detention for children under 14 unless there were exceptional circumstances.

They estimated that detention costs would triple from $37.3 million last financial year to $113.4 million in 10 years, but said if the NT adopted their recommendations to change its approach to youth detention, it would save $335.5 million in the same period.

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In a statement, Prime Minister Malcolm Turnbull said: "While most of the recommendations of this royal commission are matters for the Northern Territory, the Australian Government will now carefully consider those findings directed to the Commonwealth.

"Importantly, many of the recommendations have wider implications for all jurisdictions."

He acknowledged the courage of children and young people, and their families and wider communities for giving evidence before the commission.

"This is a serious report and the Government is committed to ensuring it carefully, comprehensively and appropriately responds to the substantial work of the Commission."