Three-quarters of young Victorians experiencing homelessness are not enrolled in school or other training, new data shows.

Only 14 per cent of 15- to 19-year-olds who connected with Melbourne City Mission's statewide service in the past year were enrolled in classes, according to the service.

Another 13 per cent were linked with other training, the data released on Thursday says. 

"Children and young people deserve a home and education," the mission's head of policy and advocacy Shorna Moore told AAP.

"They shouldn't have to choose, but that is unfortunately the current situation in Victoria."

She said most of the young students experiencing homelessness are escaping family violence.

Some 92.5 per cent of 15- to 24-year-olds accessing the mission's services have reported having mental health issues, while 58.65 per cent have an existing diagnosis. 

"Those young people who are too old for child protection and too young for adult services are falling through the gaps in the system," Moore said.

"They're cycling around with very few options to exit homelessness."

There were more than 8800 young people looking for medium- or long-term accommodation in Victoria last year, but some 5000 teens missed out on a property.  

Melbourne City Mission and the Council to Homeless Persons are calling on Victoria's next government to develop a youth homelessness strategy.

Council chief executive Jenny Smith said the strategy should include 5000 social housing properties that could accommodate young people with varying needs. 

Labor has told homelessness services it will look at providing more social housing, while the  coalition and the Greens have made promises to develop a youth strategy.

"You would always like firmer commitments, but clearly it is on the radar," Smith told AAP.

"It's a no-brainer that we invest in our future, which is what these very vulnerable young people represent."