A leading Australian researcher on Alzheimer's has won New Zealand's $NZ250,000 Ryman Prize for his work in improving the lives of the elderly.

Professor Henry Brodaty, described as the father of Alzheimer's and dementia research in Australia for his 35 years in the field, has won New Zealand's Ryman Prize.

The $NZ250,000 ($A238,674.88) prize is awarded for work that improves the lives of the elderly.

Prof Brodaty, in Wellington to receive the prize, said research into new approaches to support people caring for family members with dementia would be a significant part of dealing with the condition in the future.

There are approximately 25,100 people in Australia with Younger Onset Dementia (a diagnosis of dementia under the age of 65; including people as young as 30.

By 2020, there will be about 400,000 people with dementia and about 900,000 by 2050. Dementia is the single greatest cause of disability in Australians over the age of 65 years, and the third leading cause of disability burden overall.

Prof Brodaty said despite billions of dollars being spent researching treatments, there hadn't been breakthroughs and budget issues would become "challenging" in decades to come.

"We can't just keep building more and more nursing houses. We need to find better ways to support people at home, to support the families and to stave off the symptoms with lifestyle changes," he said.

His own work had found training and support for carers ultimately saved costs, increased their quality of life and kept people out of nursing homes and in communities longer, he said.

Prof Brodaty, who runs his own clinic, and has been a world-leading researcher and a rights advocate, said looking at prevention would be his next research focus.

"We know about a third of the cause of Alzheimer's disease is environmental. If we can attack the environmental factors, we can delay the onset because dementia largely affects people in late life; by delaying the onset by just two or five years we'll reduce the numbers of people affected by 20 or 50 per cent."

The psychogeriatrician said it was also important that people knew the condition wasn't "the end" and people could have a positive quality of life for years after diagnosis.

"It's another phase of their life. Sure it's a debilitating disease, but that's over many years."