At 60, Deb never imagined she would find herself without a roof over her head, having to resort to living in her car.

"Last year in July I was hospitalised after a person in a carpark found me in my car and I was very, very sick; I couldn't stand," she said.

"Through circumstance that was out of my control, this happened. And it could happen to anyone."

The facts on homelessness Tonight, more than 116,000 Australians will be homeless.

Tonight, more than 116,000 Australians will be homeless. That's a 14 per cent increase in homelessness over five years.

That's a 14 per cent increase in homelessness over five years. Every day, 250 people are turned away from crisis centres across the country.

Every day, 250 people are turned away from crisis centres across the country. The number of homeless people aged 55 and above has steadily increased over the past three censuses.

In 2017 the cost of Deb's rental accommodation went up, she was without work and she found herself in a position where she could no longer keep up with her bills.

"I was in private rental and was paying $230 a week for a bed sitter which was just horrible — it had no heating, no smoke alarm, no space.

"They were going to put the rent up and so I left that accommodation and temporarily went to Queanbeyan where I thought I could get cheaper accommodation.

"Cheaper accommodation was non-existent."

Embarrassed and alone

Without the option to stay with family or friends, Deb found somewhere to stay in a long-term caravan park.

"They were charging up to $500 a week, which quickly put me in the position where I had no money to pay the registration on my car.

"I ended up going through what savings I had while I was there.

"I didn't have the choice of going to be with my mother because she was very sick with dementia; she couldn't help me even if she wanted to.

"I was on my own except for my cat."

Unsure of where to turn and embarrassed by her situation, Deb sought out a car park where she could park for free with nearby access to a public toilet, a library and a supermarket.

"I would go into the public bathroom and change my clothes every couple of days but I was so embarrassed about being seen," she said.

"It was just terrible not being able to wash my hair or have a shower.

"It was the middle of winter and I would try to get some sleep in the day time because I was scared to go to sleep of a night time.

"I felt safe in the day time to doze off in the sun just sitting in my car."

For almost five weeks, Deb survived sleeping rough in her car.

Homeless people include those sleeping on the streets, in cars, at crisis centres and in overcrowded accommodation. ( ABC News: Margaret Burin )

"I was scared of people noticing that I was there and being a female on my own.

"I was scared of being physically or worse sexually assaulted."

For Deb, the experience taught her how quickly some people made judgments around others experiencing homelessness.

"It's easy to assume things about what leads people to being homeless.

"There are a lot of people who are homeless because of drug use and having no money.

"But there are all sorts of circumstances that can put you in a vulnerable position where you're on your own.

"At that time of year during winter, all the women's refuges and men's refuges are full up so there's just nothing available."

Deb found a free parking space with nearby access to a supermarket and a pubic toilet. ( ABC Canberra: Hannah Walmsley )

A lifeline from St Vincent de Paul

A local woman started visiting Deb each day to check on her wellbeing.

"She saw me getting out of the car and saw that I couldn't stand up. She called the ambulance and St Vincent de Paul," Deb said.

"I hadn't wanted to go with the ambulance because I didn't want to leave my cat on her own.

"I ended up in hospital with pulmonary embolisms to both lungs from being cramped up and sleeping in the cold.

"Tim from St Vincent de Paul had assured me not to worry and they took my cat out to the RSPCA and put her into the boarding kennels there."

And while Deb said she never learnt the name of the woman who offered her help, she would be forever thankful.

"I don't know who this kind person was but she saved my life.

"St Vincent de Paul were able to help me with transitional housing and then help me apply for government housing.

"I was just amazed. If it hadn't been for them, the Canberra Hospital and my general practitioner, I just wouldn't have survived."

The CEO Sleepout raises money for St Vincent de Paul Society homeless services. ( TravisLongmorePhotography )

The Bureau of Statistics said 116,000 people were homeless on census night in 2016, representing 50 homeless people per 10,000.

St Vincent de Paul executive Barnie van Wyk said lack of affordable housing, domestic violence, financial difficulty and health challenges were the most common factors.

In Canberra there are more than 1,500 people without a permanent roof over their heads at any given time.

"Right here in our nation's affluent capital, 531 of those people experiencing homelessness are aged between 12 and 24, and 183 are children aged under 12," Mr van Wyk said.

Each year in Canberra, business and community leaders are invited to spend the night sleeping rough as part of the CEO Sleepout fundraiser.

Mr van Wyk said the sleepout was designed to give leaders an idea of the experience of those less fortunate living in the city.

"It also raises funds critical to the continuation and expansion of Vinnies' work to support people in need with a hand up," he said.

The CEO Sleepout will be held on June 21 at the National Museum of Australia.