The Mental Health Council of Australia's latest report on the scheme predicts it will cost almost $1.5 billion, compared with the original estimate of $538 million, if demand continues at the current rate.

The council issued the report on the new Medicare services yesterday in Canberra, as part of World Mental Health Day celebrations.

Council chief executive David Crosbie said the level of service provision was ''phenomenal'' across Australia.

''In the 22 months that these new MBS items have been running, over five million services have been paid for,'' he said.

''The level of engagement by psychologists and GPs in particular is phenomenal. And it makes you ask, what does that say about the level of mental health and the kinds of issues that are happening out there and how can we better tap into that?''

The scheme was part of the former government's Council of Australian Governments' mental health initiatives implemented in November 2006.

It saw the Government begin to pay for general practitioners, psychologists and a range of allied health professionals to provide mental health services through the Medical Benefits Scheme.

This included GPs developing mental health plans for patients.

The report shows Australians are accessing mental health care at unprecedented levels.

It finds women are twice as likely as men to receive care under the scheme's services.

People living in rural Australia have less access to the new services.

To date, more than 900,000 Australians have a mental health plan.

Mr Crosbie said they knew very little about the people using the Better Access programs and whether the new services were making them mentally healthier.

''Hopefully these issues will be addressed as part of the Rudd Government's commitment to evaluate these new measures,'' Mr Crosbie said.

Lifeline Australia chief executive Dawn O'Neil said the report figures showed Australia was still trying to come to grips with the full extent of mental illness and the number of people it affected in the community.

''I think we have to as a society think about how we're going to manage the burden of disease of mental health,'' she said.

''The World Health Organisation's been very clear.

''The burden of disease for mental health is set to overtake most of the other major health burdens in the developing world in the next 20 years.

''So that is a major challenge for governments, non-government organisations, service providers and communities.''