Former NT Corrections Commissioner Ken Middlebrook, who resigned over a string of controversies and approved the tear gassing of teenagers in solitary confinement, has been appointed to the NT parole board, the ABC can confirm.

Key points: Middlebrook stood down after murderer escaped from a work camp, present during tear gassing of teenagers in solitary confinement

Middlebrook stood down after murderer escaped from a work camp, present during tear gassing of teenagers in solitary confinement Says he will not sit on the parole board until NT royal commission is complete

Says he will not sit on the parole board until NT royal commission is complete Indigenous rights activist Olga Havnen says the appointment is "just not appropriate"

Mr Middlebrook stood down as Commissioner in November last year after an axe murderer escaped from a Sentenced to a Job work camp - a program intended to rehabilitate low risk prisoners.

The incident sparked outrage from the victim's family and the then Corrections Minister John Elferink, but the Chief Minister denied Mr Middlebrook was pushed from his position, instead praising him for "hard work" and for implementing a "reform agenda".

Mr Middlebrook was also present during the tear gassing of teenagers at Don Dale detention centre and overheard on a recording telling staff: "Mate, I don't care how much chemical you use, we gotta get him out."

The former Commissioner initially justified the use of tear gas, stating that six teenagers had escaped their cells and were causing mass unrest.

But an independent report tabled last year and an investigation by the ABC's Four Corners program broadcast in June showed only one teenager had left his unlocked cell, and that tear gas was used on those inmates still contained to their cells.

Chief Minister Adam Giles blamed "a culture of cover-up within the Corrections system" for the differing accounts.

Mr Middlebrook has been appointed to the board as a "community member", effective as of June, before the Royal Commission into the Detention of Children in the Northern Territory was announced.

The former Commissioner said he had since decided to not sit on the parole board until the royal commission was complete.

"I'm not prepared to participate on the board until after the royal commission," Mr Middlebrook told the ABC.

"I've always been fair minded," he added, before declining to comment further.

A statement from the chair of the parole board, Justice Stephen Southwood, said Mr Middlebrook was appointed to the board "given his wealth of knowledge regarding Correctional Services, the principles of conditional liberty and the associated support services available".

Appointment to parole board 'just not appropriate'

But his appointment has stirred disquiet within the NT's legal fraternity, with some concerned his position is untenable given past controversies and his connections to corrections staff and inmates, although many people the ABC spoke with would not talk on the record due to the upcoming royal commission.

"It's just not appropriate. It's not good governance in anyway, shape or form," Indigenous rights activist Olga Havnen said.

"Certainly when it comes to perceptions of conflicts of interest or the lack of bias... then it's best that [parole board members] are completely removed, objective and truly independent."

Ms Havnen said it was not good enough for Mr Middlebrook to take a back seat on the parole board during the royal commission.

"Given the past roles and the experiences and the history, then perhaps this is not an appropriate appointment and serious consideration ought to be given for him to reconsider that appointment," she said.

"There are plenty of other people in the community who would bring enormous capability and competence to the role."

Justice Southwood said all issues related to Don Dale detention centre were being investigated, adding "no wrongdoing by Mr Middlebrook has been identified".