Speaking at the Royal Commission into Defence and Veteran Suicide Wagga Wagga hearings in NSW's Riverina, James Geercke said he was told to "shut the f--k up and stop complaining" while being stretchered due to a life changing spinal injury.

The injury and "indescribable amount of pain" occurred while carrying a 50 kg pack on a field training exercise and still severely affects Mr Geercke more than a decade later.

The traumatic incident was just one of several Mr Geercke experienced during his time training with the Australian Defence Force Academy (ADFA) from 2009 onwards.

It was followed by doctor misdiagnoses, extended and isolated time in hospital, dependence on prescribed pain killers and a "horrifically negative" experience seeking help from the Department of Veteran Affairs.

It would take Mr Geercke a decade to transition from military to civilian life.

"I think that can be avoidable with treatments and supports," he said.

The witness also outlined prevalent and frequent incidents of self-harm, excessive drinking and unnecessary punishments associated with a "very tough and strict" training regiment, pushing recruits to their limits.

"It was very intense at that period," Mr Geercke said.

"Everyone was stressed out all the time."

ADFA recruits, the majority of which were under the age of 20, faced the constant possibility of being charged by commanding officers for infringements, creating a "fear of failure".

Mr Geercke recalled being charged for not keeping his room tidy enough after dust was found inside his light bulb.

READ MORE:

As a result, the recruit lost a weekend's leave allowance and the infringement was kept on his record for the following 12 months.

"When you keep getting punished for things you can't achieve, it starts to have a very negative effect on your mental health," Mr Geercke said.

"It was very excessive ... it's done more harm than good."

Mr Geercke first encountered suicide in the ADF just two weeks into his training, something he "didn't think much of" at the time.

He said suicide amongst trainees then occurred once a year.

Those regular incidences were followed by "largely tokenistic" presentations about suicide prevention and warnings not to speak with media.

Mr Geercke also witnessed first-hand several incidents of self-harm.

"These were all recruits in training with me, these weren't people who had been to war," he said.

"I had been in the room when one of my friends really tried to kill himself.

"There's lots of drinking, violence and people just losing their mind, snapping, have a bit of a psychotic episode, heading-butting the wall, punching the wall, things that don't make logical sense."

These incidents were purposefully not reported out of "fear of reprisals and of being discharged".

"No one asked for help," Mr Geercke said.

Concluding his testimony, Mr Geercke said he enjoyed the work involved with Defence and the bond created with other members but his message to possible recruits was clear.

"I tell everyone that asks me not to join," he said.

"It takes a bigger toll than you realise."