Almost one in five young people have fewer hours of work than they want, with underemployment in the youth labour force at its highest level in 40 years.
When unemployment is taken into account, the proportion of people aged 15 to 24 who are either without work or enough hours of work is now at 31.5 per cent.
The so-called "under-utilisation rate" which combines unemployment and underemployment levels is higher than it was during the 1990s recession.
Josh Sandman, 19, is one of 659,000 young Australians who are either unemployed or underemployed - having some work, but wanting more hours.
He does 10 hours a week of volunteer work as a freelance graphic designer in the hope it will lead to a full-time job. He had about 20 hours a week of paid work at a takeaway food outlet in Adelaide until a couple of weeks ago.
"If I had lost my job and was not living at home I would be on a couch or homeless right now," he said.
The new Brotherhood of St Laurence analysis shows 18 per cent of young people are underemployed, the highest level it has ever been since 1978 when the Australian Bureau of Statistics first started collecting the data.
Underemployment is now much higher than youth unemployment which is at 13.5 per cent.
Unemployment was less than 10 per cent and underemployment was at 11 per cent just before the global financial crisis.
The new analysis uses data from the Australian Bureau of Statistics, the Household, Income and Labour Dynamics in Australia Survey and the Department of Employment.
To be released on Monday, the Brotherhood of St Laurence publication, Generation Stalled: young underemployed and living precariously in Australia has found that the rise of underemployment can not be explained by the growing number of young people combining study with work.
"[T]he rise in the percentage of casual and part-time jobs has mostly been among young workers who are not studying," the report says.
Young people are now far more likely to be in casual and part-time jobs now than they were in the year 2000. The gap between the actual hours worked and the hours young people want to work has widened.
"The employment outlook for many young Australians today is profoundly different than it was when their parents and grandparents first started work," said Tony Nicholson, executive director of the Brotherhood of St Laurence.
"The record growth of underemployment particularly hurts the 60 per cent of young people who don't go to university - they face a much more uncertain future than previous generations."
Mr Nicholson said in the past, young people could leave school early and get a job in a factory, mail room, bank or a state-owned enterprise get training and improve their prospects.
"They had every chance to build a good life for themselves and their families. These opportunities have shrunk as the economy has changed and insecure jobs are leading to far more uncertain prospects for the new generation," he said.
"We need to redouble our efforts to build the capabilities of disadvantaged young people in this very challenging scenario. Tinkering with welfare payments is not the answer here."
The prevalence of young workers who are not students on permanent contracts has fallen from 61.8 per cent in 2008 to 53.2 per cent in 2014.
The proportion of students in casual work has fallen in recent years.
