A 17-year-old boy has spoken out about being tormented by guards who regularly bashed and racially abused him at North Queensland's Cleveland youth detention centre.

Key points: Former detainee says he was physically and racially abused at Cleveland detention centre

Former detainee says he was physically and racially abused at Cleveland detention centre In one incident a guard spat in his food

In one incident a guard spat in his food Former workers say the boy was 'targeted' by guards

Russell Johnston told Lateline one guard spat in his food, he was not allowed outside his unit without restraints, and he was the victim of regular violent "take-downs" while inside the Townsville facility.

"They used to call me black dog, caged monkey, abo, all sorts of filthy names, mother f***er. It used to hurt me," he said.

"I'd have bruising, swelling to my face and back. There was some days I couldn't walk because my back was so sore."

Russell's claims of mental and physical abuse have been corroborated by former and current workers at the detention centre.

They told Lateline about the aggressive behaviour of a handful of staff and how Russell was targeted by those guards.

The allegations are part of a joint investigation by the ABC's 7.30 and Lateline programs into the Cleveland detention centre. The investigation follows the Four Corners report that exposed abuse at Darwin's Don Dale detention centre and prompted a royal commission into youth detention in the Northern Territory.

Former worker Graham Pattel said some staff would torment the boy to get a reaction and then respond with a so-called "take-down"; restraining him with physical force.

"I don't know why they were targeting him, other than he would challenge them every time they would torment him or tease him. They knew how he'd react," he said.

"There was no need to treat that young man with such force and humiliation.

"They broke his spirit and they broke just about everything else he had."

Guard told him 'I spat in your food'

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Russell grew up in Cairns, north of Townsville, and says he started using marijuana and ice from a young age.

He was in and out of Cleveland after getting in trouble for breaking and entering and stealing cars.

During his last stint in Cleveland last year, he said certain guards "got it in for him," and he told Lateline of numerous instances of physical and mental abuse.

One incident in particular still haunts Russell. He said that on January 23, 2015, he failed to get out of bed on time.

"You're supposed to be up by 7:15 but it was 7:16 and I wasn't up," he said.

"They came into my room, restrained me, took my shirt off, they kneed me a few times then elbowed me and stuff, my mouth was bleeding.

"When I finally got breakfast at 7:30, I received my breakfast and it was Weet-Bix and I was eating it. [The guard] rang me up in the intercom in my cell and tells me 'How does my spit taste? It's a big green one. Look under the Weet-Bix.'

"And he kept laughing. 'I spat in your food and you're eating it, how does it feel?'"

Russell said another staff member overheard the incident and he made a formal complaint, but in a written response was told the allegation "could not be substantiated".

Russell said he lived in constant fear of the guards.

"[In another incident] they started punching me in the ribs and kneeing me in the head, then they threw me on the floor and I landed onto my mate's stool and I was crying and crying," he said.

"They said: 'Shut the f**k up monkey, you're in a cage. Shut up!' They kept doing what they were doing until I stopped crying."

Russell claims that for most of his time inside Cleveland he was only allowed outside for short periods of time and his hands and feet would often be shackled when being transferred.

"It wasn't for a short time, it was for months at a time, it made me feel like an animal," he said.

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'You could set your watch' by abuse

Russell said he spent most of his time in the centre's Behavioural Support Unit (BSU), an area of four cells isolated from the rest of the centre and used for children considered to be causing trouble in the prison.

One former worker, who wants to remain anonymous, told Lateline she worked one shift in the BSU and witnessed a staff member tease Russell until he snapped and they took him down.

"The whole situation could have been avoided if they didn't bait him," she said.

A current worker in the facility said she too had concerns for Russell's welfare.

"There was no need to treat him like that. These kids come from pretty tough backgrounds as it is, they often get violence at home, they need to be shown that there's another way."

Mr Pattel and other workers at the centre have acknowledged that take-downs and restraints are necessary tools to deal with troubled children, but said they are methods of last resort and in Russell's case were used excessively.

"It was pretty much every day. They'd call a code almost everyday on Russell. You could pretty much set your watch to it," he said.

Guards have told Lateline that Russell was known to have behavioural issues and a short fuse, but teasing and torment exacerbated his problems.

Some staff members, including Graham Pattel, said they had a good rapport with Russell but when they offered to help, they were told to "take care of their own unit".

He has now been out of Cleveland for almost a year and is still traumatised by his experience.

"I see my psychologist about four times a week and I'm on medication just to help me get to sleep," he said.

"I still have bad dreams about the staff coming in the morning, waking me up. Cleveland scarred me for life."

Queensland Attorney-General Yvette D'Ath said she could not comment on individual cases for legal reasons.

"In Queensland all the allegations that have been put to the department over a number of years have been thoroughly investigated and referred to police or other investigative bodies where appropriate," she said in a statement.

"Incidents have been detailed in reports, and recommendations have been made for reform and been put into action."