Mike Fletcher left the detention centre in 2016 after almost three years on the frontline as a youth worker.

He said in that time he witnessed several uses of force that were, in his opinion, both inappropriate and potentially illegal.

“The one that sticks in my head the most is when I was directed to restrain a young boy, tie his hands behind his back with plastic zipties and directed to lock the child in his room with his hands tied behind his back,” he said.

“The boy spent the next 15minutes rolling around on the floor crying as he continued to trip over whilst trying to stand up with his hands tied behind his back.

“The staff present found this very humorous for some reason.”

The gravity of the situation, which occured in 2015, did not bite until Mr Fletcher left the youth detention centre that night.

“I remember getting home from work and nearly breaking down in tears at what I had witnessed as I couldn’t believe a child could be treated so poorly,” he said.

Mr Fletcher, who has a social science degree and was studying for his masters while working at the facility, is the first youth worker to speak on the record about recent allegations of abuse inside Bimberi.

“Other use of forces I witnessed involved a young person being kneed on the ground by three staff in their cell,” he said.

“[As well as] a young person being dragged along the ground on their stomach and back and a young person choked on the ground by a staff member until their face went blue.”

Some staff had referred to detainees with racially insensitive and abusive language, Mr Fletcher said.

“On many occasions I heard staff refer to YPs as junkies, black c----, scum, and filth,” he said.

Mr Fletcher was highly critical of the ACT government’s responses to allegations of abuse inside Bimberi, and said the reputation of the centre had been prioritised over the human rights of detainees.

“I would 100 per cent support a truly independent inquiry into Bimberi and have assisted in any way possible with the current human rights investigation,” he said.

“I believe the inquiry should review the CCTV footage of all uses of force and make these available to a member of the opposing political party who can truly be independent.”

Mr Fletcher said he left Bimberi in 2016 to work elsewhere within the ACT Community Services Directorate.

He recently moved away from the ACT and now works as a youth worker for a not-for-profit organisation in NSW.

The Community Services Directorate was asked about a series of alleged incidents inside Bimberi last year, including the same incidents now mentioned by Mr Fletcher.

The directorate did not comment on specific incidents, although it said it was aware of some allegations and that these had been appropriately reported and responded to at the time.

The ACT government’s executive director of youth services Dr Mark Collis said the territory had the best youth detention centre in Australia.

"I would maintain we're not seeing the same problems as occurred pre the 2011 report [by the ACT Human Rights Commission]," Dr Collis said in July 2017.

"There have been huge improvements.

“We have reduced the use of force in Bimberi, we have reduced assaults in Bimberi. We have improved the numbers of people returning to Bimberi so I think the community needs to celebrate the staff and the work they do every day of the week."

The new Bimberi Headline Indicators Report, tabled last month in the legislative assembly, showed there have been more assaults between detainees inside the facility and the use of force is on the rise.

The report showed there had been 10 assaults among detainees inside the centre in the last six months of 2017, compared with just six for the 12 months between July 2016 and June 2017.

Assaults are defined by the directorate as an "intentional act of direct infliction of force or violence".

There were 84 uses of force in 2016-17, compared with 89 uses of force in just the last six months of 2017.

The ACT Human Rights Commission is investigating allegations of abuse inside the Bimberi Youth Justice Centre.