And he thinks this culture shock contributes to a suicide rate amongst his peers that is 14 per cent higher than the general population.

"You picture a car going 100 kilometres an hour, and just stopping it. That's pretty much what it feels like, coming out of Defence," Mr O'Keefe said.

"One minute, you're fit and you're strong, and the people you work with are your family - and when you get out, it's like the umbilical cord's cut."

Mr O'Keefe was just 17 when he applied online to enter the Australian Defence Force.

"I'd had enough of school in year 10, and mum said to me I couldn't leave school unless I had a job to go to," he recalled.

"So I went online and applied for the Army, came out and told mum and dad, and they were like 'That's good', and that was it."

The young Beechworth man went to East Timor in 2008 as part of the 5th Battalion of the Royal Australian Regiment, but that peace-keeping deployment was "like a holiday" compared to Operation Slipper in Afghanistan in 2010 and 2011.

"The first day we actually got out to our forward operating base, one of the Americans was killed. That was a bit of an eye opener, that this was actually a war," he said.

"You go over there thinking one thing, and then you see a different side.

"These (Afghan) people had lived through wars for 2000 years and no one had dislodged them. They were really humble.

"Unfortunately, what's happened with the war crimes inquiry, is it's tarnished everybody.

"People think everyone was doing the wrong thing over there, even though it was a select group of people from a select unit."

Medically discharged after nearly 14 years in 2017, the now-33-year-old said he "didn't know what to do" on the day he came out of the Army.

"I was like, I don't have to shave. I don't have to call anyone on sir or ma'am," he said.

"And you realise that there's no one there that gives a s**t. You've got family, but you try to blend in with them and your mates ... it's a difficult concept for people to understand.

"I've been seeing psychs and stuff for years, since I came back from Afghanistan.

"I had to get on top of myself, because as everyone said, you can't look after somebody else if you're not looking after yourself."

The father-of-four, now remarried and living in Wodonga, said a serious motorbike accident and being confined to a spinal brace led him to confront his mental struggles.

He is now "in a good spot" and looking at promising new job prospects, but knows too many veterans who were lost before they could get help like him.

"I can't even count on two hands anymore the people I know that have taken their own lives," Mr O'Keefe said.

"I either worked with them, or I was on the same base as them.

"That's the hardest part - every time I see it, I go 'Who's next?'"

A growing movement on social media is calling for a Royal Commission into the high rates of suicide among veterans.

As recently as March 5, 'Vets we Forget' disclosed another well-known member who died, a Navy clearance diver.

With each death, more signatures are added to a petition by Julie-Ann Finney, who lost her son David in 2019.

The petition opposes the appointment of The National Commissioner for Defence and Veteran Suicide Prevention, and instead calls for "a fully-empowered, independent and transparent Royal Commission".

A Department of Veteran's Affairs spokeswoman said the Commissioner would have the "powers of a Royal Commissioner".

"Suicide prevention is one of this government's highest priorities," she said.

"The sad reality is that suicide is a very complex issue and prevention is a difficult and unrelenting challenge for all Australians.

"The government is committed to putting veterans and their families first and spends more than $11.5 billion each year to support 325,000 veterans and their families."

All ADF personnel who have joined or transitioned from Defence are automatically registered with DVA, which gets in contact with supports.

Mr O'Keefe doesn't have the answer for reducing veteran suicide rates - but he knows something more has to be done.

"The stigma with men is that we don't talk about it, because it's not cool, it's not tough. But if you don't talk about it, it just sits there bottled up," he said.

"That concept, that people don't have anywhere to go, it's getting better.

"There's a lot more veterans that are taking up positions where they can help others. But I think Defence needs to do a better job at helping to ease people into civilian life again."

A new $5 million veteran well-being centre in Wodonga's CBD, a federal government initiative, "will be the absolute premier Victorian, if not national" one-stop-shop of its kind.

An announcement about its location is expected soon.

Mr O'Keefe is hopeful it will be welcoming and accessible to all veterans.

Meanwhile, he is taking part in the 'March On' fundraiser organised by the national not-for-profit Soldier On, launched in 2012 to support the veteran community.

More than 6000 participants are walking 96 kilometres (the length of the Kokoda Track) throughout this month to support mental health services for returned ADF members.

Mr O'Keefe, who traversed the real Kokoda Track while still in the Army in 2014, has completed nearly 30 kilometres by walking Hunchback and Federation hills.

"It's close to heart, because ... I've fought through a lot with my injuries," he said.

"Soldier On does coffee catch-ups, getting people together and talking, with no uniforms or ranks.

"I want to raise $2500, as $500 raises enough to send 25 veterans to a few courses to get them into employment.

"If it's that little bit to help them on their path back to normal, that's what it's about.

"It's helping to prevent people from being statistics."

To support his cause, go to https://fundraise.soldieron.org.au/sponsor and search for Mick O'Keefe.