Youth homelessness rising as housing crisis bites

Almost a quarter (23 per cent) were aged 12 to 24, with another 14.4 per cent under the age of 12.

Based on the figures, more than 43,000 Australian children and young people could be without a home each night.

Harry Sanders was forced to couch-surf and sleep at homeless camps and under a Melbourne bridge after he was kicked out of home at age 17.

The teenager was homeless for almost a year but narrowly graduated from high school and moved into a share house.

"I finished school and didn't have the money to do university," the 26-year-old told AAP. 

"My social worker encouraged me to go to an event and I met a business mentor, who encouraged me to work on a business that I started before I got kicked out of home."

He went on to establish StudioHawk, Australia's largest dedicated search engine optimisation agency, employing about 80 staff and collecting roughly $13 million in revenue a year.

Mr Sanders used to feel embarrassed by his past but is speaking to destigmatise the subject and push for more resources to snap the "ruthless cycle".

"We've got all these young Victorians and Australians on the street and some of them won't seek help," he said.

"Youth homelessness is a lot easier to solve because there are a lot less mental complications.

"But if you don't solve it when they're young, it becomes a long-term problem and costs us an absolute fortune."

Eamonn McCarthy, chief executive of youth homelessness charity Lighthouse Foundation, said the number of homeless youth was growing.

"Mental health issues among children and young people are on the rise," Dr McCarthy said.

"Family violence has increased and the higher cost of living, paired with the housing crisis, is pushing more children, young people and families to the brink of homelessness."

The types of children needing help from the Victorian-based homelessness foundation are increasingly younger.

"Some of the challenges we may historically have seen for kids who are 15, 16, 17 are now being seen in children as young as seven, eight, and nine," Dr McCarthy said.

Some 268 life-size cut-outs will be placed on the steps of Victoria State Library on Wednesday to represent the most recent figure of people under 25 sleeping rough in the City of Melbourne area.

The installation is part of a wider campaign in schools and coincides with Youth Homelessness Matters Day.

Lifeline 13 11 14

Kids Helpline 1800 55 1800 (for people aged 5 to 25)