A Mission Australia survey of 15-19-year-olds has found one-in-six experienced homelessness last year, prompting calls for a national homeless strategy.
One in six young Australians have experienced homelessness, with family violence the leading cause for them to leave home, new data shows.
For the first time in its yearly survey of 15-19-year-olds, Mission Australia asked young people if they had spent time away from home in the past three months because they felt they couldn't go back.
The results, released on Wednesday, show an average of one-in-six young people across the nation answered 'yes' in 2017, with the highest rates in Western Australia (one-in-five) and the lowest in Victoria (one-in-eight).
Mission Australia CEO James Toomey said the charity decided to gather data after hearing reports from its service providers that homelessness among young people was increasing.
Young people often experienced "hidden homelessness", where they live in refuges, transitional accommodation or couch surf, he added.
"Family and domestic violence is the leading cause of homelessness," he told AAP.
"With young people that might look like choosing to absent themselves from the family home.
"It also means that children leaving with an adult, or with a parent, are finding themselves homeless as a result of that."
Mr Toomey said young people who leave state care, such as foster homes or residential placements, were also at risk of homelessness due a shortfall in affordable housing.
Mission Australia is calling for a national homelessness strategy, with a particular focus on preventive measures for young people.
"That would mean working within family systems to stabilise and support families where there may be family dysfunction or family violence," Mr Toomey said.
"Or strategies to leave home safely and move into suitable accommodation."
The survey also found that almost one in five who had couch surfed had first experienced it when they were under the age of 12, and for the same percentage, couch surfing was not an isolated experience.
Seven per cent of young people stayed away from home for periods longer than six months.
Removing stigma around the issue was an important step forward, Mr Toomey said.
"Giving people the opportunity to talk about their experience with homelessness, and therefore, destigmatising it, to access support available to them."
Mental illness often played a significant part in young people experiencing homelessness, and the two issues often exacerbated each other, he added.