A landmark teen depression study announced by the federal government will put smartphones to the test.

Mental health apps will be trialled by thousands of Australian teenagers to test their effectiveness in preventing depression.

The Black Dog Institute will recruit 20,000 Year 7 students to trial the apps as part of a landmark study announced by Federal Minister for Health Greg Hunt on Wednesday,

Lead by Professor Helen Christensen, researchers will examine sensor data collected from smartphones such as GPS, use machine learning analysis and link this to hospital and birth records to develop reliable signals to flag the onset of depressive symptoms in young people.

The Future Proofing trial - to commence in 2019 - will also examine whether cognitive behavioural therapy (CBT)-based apps are effective in reducing symptoms of anxiety, eating disorders, suicide risk and psychotic symptoms, as well as its impact on academic performance, sleep, physical health and drug and alcohol use.

"This study will be unlike any previously undertaken in youth mental health in Australia, both in terms of scale and potential impact," said Professor Christensen.

With one in five Australians experiencing a mental illness each year, treatment alone will not be enough to reduce the burden of depression and there needs to be a greater focus on prevention, Prof Christensen said.

"Up to 75 per cent of mental illnesses emerge before the age of 25, making early intervention in the teenage years critical to prevent the onset of poor mental health outcomes over the life span."

The National Health and Medical Research Council (NHMRC) project is one of 47 announced Wednesday as part of the federal government's $53 million commitment to innovative mental health research.