The number of Australians who will develop dementia by 2050 could be cut by one-third if research breakthroughs can delay its onset by just five years, according to a new analysis.

New medicines to delay or slow the progress of major diseases that lead to dementia are currently under trial.

But current research efforts are slower and more difficult than hoped.

A report commissioned by Alzheimer's Australia, released on Tuesday, shows that even small breakthroughs - delaying the onset by two or five years - could dramatically reduce the number of people who contract the disease.

The report, Modelling the impact of interventions to delay the onset of dementia in Australia, was prepared by the Dementia Collaborative Research Centre (CRC) at the University of New South Wales.

It's estimated that almost 900,000 people will live with dementia in 2050, about three times the current number.

Between now and 2050, more than three million people in total are likely to develop the disease.

If research comes up with a way to delay the onset by two years, and it is put into practice in 2020, it could reduce the number of people developing dementia by almost 400,000.

And if interventions or treatments can delay the onset from average age 85 to age 90 then almost a million people would be spared.

This means their quality of life would be greatly improved from if they had developed the disease, and they and their carers would be free of the stigma, loss and grief dementia brought, the report says.

Reducing the number of people likely to contract the disease would also lessen the burden on health systems.

Alzheimer's Australia has used the findings in the report to renew its calls for an extra $200 million to be put into dementia research over the next four years.

"While Australia can claim many world leading scientists, the dementia research sector lacks capacity and has been falling behind other health research areas for over a decade," president Ita Buttrose writes in the report's foreword.

Dementia CRC director Henry Brodaty said research had already found lifestyle changes people could make to reduce the risk of dementia, including looking after body, brain and heart.

"But, in the long term, an increased investment in dementia research is the only hope we have for the development of medical interventions to delay, stop or reverse the diseases that lead to dementia," he said.