Dr Nicolas Cherbuin, from the Australian National University's Centre for Research on Ageing, Health and Wellbeing, said there were currently 300,000 dementia sufferers across the country, which would increase to about one million by 2050.
The direct health costs of dementia were about $5 billion a year, he said.
However, if risk factors such as depression, lack of exercise and poor diet could be reduced by a tenth, the number of new dementia cases would fall by 3.3 per cent annually.