An explosion in the Nando's chicken shop below his Sydney apartment ripped his home apart and left a traumatised Mr Parry with neurocognitive disorder, starting him on a "downward spiral" that led him to Canberra this week.

"I’ve gone from a six-figure salary, [speaking] eight languages and travelling around the world to sleeping in parks," Mr Parry said.

"I’m trying to show people that [homeless people] come in all shapes and sizes.

"I can walk around Canberra and you would not even detect that I have no address or that I’ve been through this sort of trauma, because people expect a certain stereotype."

Mr Parry arrived in Canberra this week after completing an 18-day "hike against homelessness" to raise awareness of the role mental illness plays in making many Australians homeless.

He said he wanted to show that the challenges of walking from Melbourne to Canberra were not all that different to the everyday struggles facing homeless people, many of whom end up without a fixed address because of a split-second incident beyond their control.

During the walk, funded largely through GoFundMe, Mr Parry lived on $39 a day and slept in parks, beside rivers and on strangers' couches.

Just with everyday life, not everything went to plan. While he expected his feet to ache, he didn't anticipate having to walk for long stretches at night in an attempt to avoid swooping magpies.

"You've got things thrown at you, as you do in life," he said.

"The magpies swooping you; that could represent financial problems that come from day to day."

According to the Australian Bureau of Statistics, 116,000 people were homeless on census night in 2016.

In Canberra, the number of homeless people seeking shelter reached record highs in 2018, with Safe Shelter ACT taking in 95 homeless men for a total of 743 "guest nights" in the 23 weeks it was open between April and September. The number of "guest nights" almost doubled from 379 in 2017.

Mr Parry does not fit the stereotypes most people associate with homelessness.

After the 2008 explosion, the 47-year-old spent years "in denial" of his deteriorating mental health and "jet-setting around the world, spending like crazy".

But he's tired of "escaping on a plane" and while he has been able to work overseas without a fixed address, he wants to live in Australia again.

Without an address and with a mental health condition that means he is often unable to remember basic things like where he was the day before, he has been unable to find work since returning from Malaysia four months ago.

"If you don't have a home, how do you get a job, and vice versa?" Mr Parry said.

He hopes sharing his story will remove some of the stigmas around homelessness and mental health.

"We just have to lie," Mr Parry said of addressing questions about mental health conditions on job applications.

"Just like when we're 17-year-olds getting into a nightclub, you've just got to give them a little white lie and say, 'Mental health? Me? No.'

"That's what they want to hear, but it shouldn't be like that."