Western Sydney and coastal regions will be the areas in NSW most heavily impacted by dementia: study growth rates, new dementia prevalence rates show.

The number of elderly people in NSW with dementia will more than double over the next 40 years, according to projections.

NSW faces a predicted increase from 109,000 present cases to 272,000 by 2050, according to figures prepared for Alzheimer's Australia NSW by Deloitte Access Economics.

Western Sydney and coastal regions will be the areas in the state most heavily impacted by dementia growth rates, the charity said.

Dementia will touch the lives of most people living in NSW, if not by developing it themselves, then by caring for a family member or close friend, said Professor Henry Brodaty, the co-director of the Centre for Healthy Brain Ageing and Medical Advisor to Alzheimer's Australia NSW.

More than one in eight Australians alive today are likely to develop dementia between now and 2050 without new treatments or interventions, he said.

"We need to continue to invest in research to find ways to prevent or delay the onset of dementia, while ensuring we provide appropriate care, support and the best quality of life we can for those already living with the condition."

Top 10 areas of NSW where dementia prevalence is expected to be highest by 2050:

1. Camden, (4,828 people by 2050)

2. Macquarie Fields (4,222)

3. Strathfield (3,883)

4. Liverpool (3,802)

5. Tweed (3,794)

6. Campbelltown (3,731)

7. The Entrance (3,555)

8. Bega (3,542)

9. Wyong (3,498)

10. Port Macquarie (3,496)


Copyright AAP 2014