The sister of a young man who featured in last night's Four Corners story about abuse of young offenders in the Northern territory, says his life was stripped from him after being mistreated in Darwin's Don Dale Youth Detention Centre.

Kirra Voller said she struggled to watch as her brother, Dylan, was shown being stripped naked repeatedly, thrown across the room and hooded and held in a chair for hours.

"[I] honestly believe if any young man had have walked into that cell with a loving heart and just sat down and talked to my brother and helped him through everything that he was going through, he would have sat down and played cards happily with any of those guys, but they all used force and acted intimidating and scary," she said.

Dylan Voller needed emotional support, his sister Kirra says. ( Supplied )

Ms Voller said rather than helping her brother, the detention centre staff caused him more damage.

She said they had to be held to account for their actions.

"These people are already full-grown adults and made that decision to harm that child while they were working," she said.

"I feel like those people who did that themselves, they're responsible. They took that job on. The Government gave them … that responsibility to care for these kids.

"Instead they abused that role."

Dylan was one of six children tear-gassed at the Darwin facility in 2014, sparking widespread outrage on social media, with Human Rights Commissioner Gillian Triggs calling for an independent inquiry into the treatment of Northern Territory children in detention.

In the wake of the Four Corners program airing, Prime Minister Malcolm Turnbull said he would establish a royal commission into juvenile detention in the Northern Territory and John Elferink, the minister responsible for young detainees in the Northern Territory was sacked.