There's no more urgent or important problem in Australia than tackling the mental health sector, says one of four people leading the Victorian royal commission.

Australia urgently needs to tackle its mental health system, says one of the four people leading the country's first royal commission into the sector.

Commissioner Allan Fels, whose daughter has experienced schizophrenia for more than 20 years, says mental illness can have a devastating effect.

"There's no more important problem, no more urgent problem to fix in Australia than mental health, but it's been a low priority for governments," Professor Fels said.

"From time to time it rises to the top of the policy agenda but then gets displaced by other things until there's yet another crisis."

Prof Fels, along with commission chair Penny Armytage and fellow commissioners Alex Cockram and Bernadette McSherry, start the inquiry's first public hearings from Tuesday.

The stigma attached to mental health and suicide prevention will be among the key themes of the initial hearings.

The public hearings are on until July 26, running daily, and are open to the public, but will also be live-streamed on the commission's website.

"These public hearings are an important next step for the Royal Commission into Victoria's Mental Health System and will provide people across the state with an opportunity to voice their first-hand experiences, whether it's good or bad," Mental Health Minister Martin Foley said.

"With one in five Victorians experiencing a mental illness, we know our current system is not coping and this is our opportunity to find out what is working, what isn't and what we need to change."

Mr Foley said anyone who has experience with mental illness or Victoria's mental health system should make a submission, which can still be made online until July 5.

The inquiry is due to hand over an interim report in November and a final report in October 2020.