Alzheimers Australia warned on Friday that nearly a million Australians will have dementia by 2050 and more than a quarter of them will be without care unless the government increases the number of carers and nursing homes for the aged.

From today's 257,000, the number of people with dementia will increase to more than 981,000 in 2050, according to the group's report prepared by Access Economics.

Alzheimer's Australia Chief Executive Glenn Rees said the average 8,500 community packages and residential places for dementia sufferers established annually over the past four years should be doubled to 17,000 new places a year from now to accommodate the expected increase in people with the disease.

'The undersupply of aged care places and the underfunding of community care will mean greater carer stress and older Australians being forced out of their homes early and into a nursing home,'' Rees warned, according to

The dementia crisis is being linked to the government's failure to take into account the number of people living beyond age 85. The government's basis for the number of community aged care packages and residential care places was the number of Australians over 70.

Rees said expanded care services, prompt diagnosis, more research funding and education programs are needed to address the dementia crisis.