The parents of a nine-year-old boy have questioned whether a boot camp run by Defence Force veterans can handle children with severe behavioural difficulties after their son was restrained and sent home early.

Key points: Nine-year-old Noa Cthurmer attended Veterans 4 Youth boot camp

Nine-year-old Noa Cthurmer attended Veterans 4 Youth boot camp Noa has behaviour difficulties and argued with, hit and spat at a trainer and was sent home

Noa has behaviour difficulties and argued with, hit and spat at a trainer and was sent home Noa's parents say the trainer didn't handle the situation well

Noa Cthurmer was attending an eight-day boot camp on the Queensland Sunshine Coast held by Veterans 4 Youth, a for-profit organisation that started running the camps this year.

During breakfast on day five of the camp, Noa told another boy to move from the table. When a male instructor intervened a heated argument began between Noa and the adult, culminating in Noa spitting at and hitting the man in the face.

Another male instructor restrained Noa and told the other instructor to "walk away".

Noa was taken outside and later asked to leave the camp.

The incident was filmed by 7.30.

Trainer 'behaved like a little kid'

Noa Cthurmer argues with the boot camp trainer. ( ABC News )

When 7.30 showed footage of the incident to Noa's parents, Deborah and Michael Cthurmer, his mother said it "broke my heart".

The Cthurmers, who have a farm in the New South Wales Blue Mountains, said they had informed Veterans 4 Youth about Noa's challenging behaviour.

"Noa is diagnosed with oppositional defiance disorder and he also has Tourette Syndrome. The main problem would be anger," Ms Cthurmer said.

"That [incident] just shows me there's a complete lack of experience from their side there dealing with that.

"They embarrassed him, they belittled him in front of everybody."

Mr Cthurmer asked: "Who has got more muscles?"

"[The trainer] behaved like a little kid. No experience at all. Nobody won in that and that to me seemed like a competition of who was bigger. He was into his face," he said.

Deborah and Michael Cthurmer say the trainer "showed a complete lack of experience" in dealing with Noa's behaviour. ( ABC News )

Ms Cthurmer said the incident could have been avoided.

"It didn't need to erupt like that, that was huge and that could have been potentially dangerous for everybody involved and Noa didn't take it to that level," she said.

When Noa got home from the camp he told his parents he "failed".

"As I told him, 'You didn't fail, they failed you. You're the one with the problem, they're the ones that are supposed to help you'," Ms Cthurmer said.

'A stern approach is important'

Noa Cthurmer at home with his father Michael. ( ABC News )

Veterans 4 Youth defended how it handled the incident.

"We've counselled Noa several times over the last few days," counsellor Jeremy Couch told 7.30 at the camp.

"I think where other children's safety is at risk, I think a stern approach is important because our philosophy is about the safety of the whole group."

This was the first time the boot camp has been held for boys as young as nine.

"We're not recruiting for the Army, we're not trying to turn them into soldiers," CEO Leo O'Reilly said.

"It's about turning them into responsible, reliable, dependable young adults.

"We teach them a values-based decision-making system, so values like honesty and integrity, loyalty, mateship and work ethic.

"Most of the instructors here have some experience training youths. They've either been recruit-training instructors in the Army, Navy or Air Force."

So far it is unproven whether the discipline enforced in the camps results in lasting behavioural changes.

Veterans 4 Youth is working to build up the evidence base.

"This is the first time we've ever actually measured the results. We actually want to get some numbers that we can put to our results," Mr Reilly said.

"What we've started is a survey before they come on the course where the parents rate them on different levels of behaviour. We'll give them another survey to complete at the end of the course and a similar survey in three months time."