The Royal Flying Doctor Service says there is a crisis in rural and remote mental health services.

Flying Doctors chief Martin Laverty says there is an enormous disparity between country and city services.

“We see [more remote] people only accessing mental health services at … 20 per cent the rate of those who access services in the city,” Mr Laverty said.

“If that's not a crisis, I don't know what a crisis is.”

The charity provides vital medical care to people and the most remote parts of Australia, but says its doctors are becoming overwhelmed by the amount of psychological support they must provide to patients.

“Last year the Flying Doctors saw 24,500 people to provide mental health counselling, but we could double or triple that service tomorrow and still not touch the surface,” Mr Laverty told the ABC.

Health Department data shows that while the number of registered psychologists nationwide increased in 2015/16, but even so, 15 rural and remote areas are still without any registered psychologists.

Areas including west coast Tasmania, central Australia, western Queensland and the Kimberley in Western Australia are among those missing out.

“Areas where perhaps you're not surprised to see that there aren't health professionals in abundance,” Mr Laverty said.

Rural suicide rates are 40 per cent higher than major cities, and almost double in more remote areas.

The Coalition put up $80 million for psychosocial support services in last year's federal budget, but made the funding conditional on the states and territories providing funds too, which has not happened.

Health Minister Greg Hunt has acknowledged more assistance is needed.

“I do believe there is a very significant challenge and this is because there are four million Australians every year who have some form of mental health challenge and in the rural areas this is a significant challenge which is precisely why we are looking at additional services,” he said.