Youth detainees in the Northern Territory are being denied access to fresh air, sunlight and exercise as well as appropriate education, two detainees have alleged in a lawsuit exclusively obtained by the ABC.

Key points: Northern Territory Legal Aid Commission files lawsuit on behalf of two youth detainees, alleging human rights abuses

Northern Territory Legal Aid Commission files lawsuit on behalf of two youth detainees, alleging human rights abuses Detainees denied sunlight and access to regular exercise, lawsuit alleges, alongside mental health support and welfare programs

Detainees denied sunlight and access to regular exercise, lawsuit alleges, alongside mental health support and welfare programs NT Government vows to fight the claim, arguing it has made progress on the royal commission recommendations

The lawsuit, filed by the Northern Territory Legal Aid Commission on behalf of the two detainees, alleges human rights abuses in the Territory's youth detention centres are still current, despite a royal commission handing down a damning report on conditions last year.

It claims children are being denied access to exercise — including a minimum of two hours outdoor recreation or exercise per day for children not subject to segregation orders — and suggests detainees are not receiving access to education by qualified teachers, for a minimum of five days a week, for 40 weeks a year.

Other allegations include:

Children are separated from the main detention population when "other courses of action are reasonably practicable"

Children are separated from the main detention population when "other courses of action are reasonably practicable" Emergency management protocols and individual care plans are not being followed for children at risk of self-harm

Emergency management protocols and individual care plans are not being followed for children at risk of self-harm Accommodation is not "safe, clean, hygienic or reasonably private"

Accommodation is not "safe, clean, hygienic or reasonably private" The number of detainees per cell exceeds the permitted allocation, and observation cells are being used for general accommodation

The number of detainees per cell exceeds the permitted allocation, and observation cells are being used for general accommodation Access to mental health care and support is not consistent with what is available to a child in the general community

In a report handed down in November, a royal commission examined in detail previous conditions within Darwin's Don Dale and the Alice Springs youth detention centres.

But the new lawsuit is alleging these human rights abuses are current, and that the Government "has breached, is breaching and threatening to continue to breach the duties owed to young people under the Youth Justice Act".

Facilities should be immediately closed, commission says

Northern Territory Chief Minister Michael Gunner said the lawsuit was "five years too late, against the wrong government".

The period examined by the royal commission found iterations of both Labor and Country Liberals governments had failed in their duties to young people in detention during their terms of government.

Mr Gunner has vowed to fight the lawsuit and said his government was in the process of implementing the recommendations from the royal commission.

"I believe we're doing everything we can to fix this problem, I believe we're investing and have the runs are on the board," he said.

"We're investing in the current facilities while we're working on the new facilities, so everything they could possibly ask for to make a difference, we are doing," he said.

The application is asking for the Minister for Territory Families, Dale Wakefield, to "rescind the approval of the centres as youth detention centres".

It also asks the court to prevent the Northern Territory Government from continuing to use either the Don Dale or the Alice Springs youth detention centres until such time as the conditions are rectified.

Both the minister responsible, Ms Wakefield, and the Chief Minister have publicly acknowledged neither centre is "fit for purpose".

Ms Wakefield said sufficient renovations and staff training had been carried out to satisfy the needs of detainees until new facilities could be built.

Previously, the CEO of the North Australian Aboriginal Justice Agency, Priscilla Collins, said almost all of the children in the Northern Territory's detention centres were on remand, and could therefore be released into supported bail accommodation or the community.