He has been a long-time advocate for people suffering from mental health, after his son Shane took his own life in 1993.

"Suicide has now become - and this is a terrible phrase and if it shocks people, good - the greatest killer of people in Australia," Mr McGrath said.

"More than 3000 people are dying every year from suicide - that's eight people a day - it's a disgusting statistic to have."

In recent weeks, the chief of headspace Jason Threthowan has admitted the organisation has growing challenges.

He spoke about the missing middle, something that Mr McGrath agrees with.

He said that Professor McGorry believes in the early intervention model for headspace, but a lack of funding meant the organisation could not always help people at this point.

"I talk to people at headspace centres around Australia and they are saying 'we can't deal with the number of people coming in - we can't give them the hours they need or we can't get to them at all'," Mr McGrath said.

As a result, people are too sick for headspace and not sick enough to access the limited services on offer for people battling mental illness.

"There's something wrong with the treatment regime," Mr McGrath said.

He said the old model of sending people with mental health issues to institutions was too heavy handed, but he feared the new model often saw people released from care too early.

Mr McGrath said he believed this was the case for his son, who had suicidal ideations in the lead up to his death.

"I lost a son in 1993," Mr McGrath said.

"Shane was 28 and we had wrestled - and I deliberately use that word - with the mental health system for about 10 years."

Mr McGrath said his son was an intelligent man, but he got frustrated with the lack of support offered to him by the health system.

"When he couldn't achieve what he wanted to achieve he became frustrated with life and decided enough was enough," he said.

Mr McGrath said he begged doctors to keep his son in hospital after he finally agreed to go and seek treatment.

But his pleas fell on deaf ears.

"He should have still been in hospital and sadly I don't think a lot has changed. I don't think there are enough beds."

Mr McGrath said extra funding for the mental health system was desperately needed, given that 20 to 25 per cent of the population suffers from some sort of mental health issue.

"We need more money, that's the bottom line," he said.

"They've got to get fair dinkum and do something about it."

Mr McGrath said when headspace was first set up, the aim was to help people aged 12 to 25, but this quickly changed due to a desperate need, which meant a higher level of funding was needed.

"We set up a schools program - we were thinking secondary schools - but we started to find suicidal ideations appearing in children as young as 8."

Mr McGrath said another impact of removing the stigma associated with mental health was that a larger number of people were seeking treatment, placing greater pressure on the system.

He has worked with organisations such as beyondblue, headspace, Crisis Support Services and The Mental Health Professionals Network.

If you or someone you know is experiencing an emotional crisis, call Lifeline on 13 11 14.

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