Last year's Australian of the Year, Patrick McGorry, says lives will be lost unless the federal government delivers on its promise to make mental health a priority.
In the election campaign last year, Prime Minister Julia Gillard announced the government would allocate $277 million for a program to tackle suicide.
Speaking at an Australian of the Year function in Canberra, Professor McGorry said significant new investments must be announced in this year's budget.
"Two houses of parliament passed very significant motions towards the end of last year endorsing major investment in mental health care and the prime minister said it would be a second-term agenda," he said.
"So, we will know in May if that's just rhetoric or a genuine commitment."
He urged that the funding be allocated in the right way.
"The money is important. But it's got to be put into new models of care, not more of the same.
"We can do it because Australian innovation has created the models and we've got to actually invest in them.
"That will only happen if the general public make it very clear to the prime minister and the coalition and all political parties that this has to be done."
Afterwards, Prof McGorry told reporters the consequences of not making a significant investment in mental health were very clear.
"There'll be unnecessary deaths from suicides and other premature deaths relating to mental illness.
"We'll see another generation of lives thwarted and constrained as a result of the disability from mental ill-health and this would all be highly preventable. So I'm hoping we don't see that."
But, Prof McGorry added, he was "pretty optimistic."
"I think the mood of the country and of all of the political system is in the other direction."
Prof McGorry's confidence was in contrast to his feelings about egalitarianism which, he said, Australia is in danger of losing.
He said inequality contributed to all the social evils society struggled with.
"Failed education, teenage pregnancy, mental illness, violence in society, rates of imprisonment ... all of these things have a direct relationship to how unequal a society is.
"Australia has been, traditionally, a pretty equal society. In that respect, we're moving in the wrong direction.
"And that's why we're seeing increasing rates of mental illness and violence."