The number of New Zealanders living with dementia will increase by close to 300 per cent to 170,000 by 2050, a new report estimates.

The Economic Impact of Dementia report, carried out by Deloitte and commissioned by Alzheimers New Zealand, was launched at Parliament tonight by Seniors Minister Maggie Barry.

Catherine Hall, Alzheimers NZ chief executive, said new models of care were urgently needed as dementia cases in New Zealand triple over the next 30 years.

"The blueprint for these models of care already exists in the government's NZ Framework for Dementia Care that was written four years ago," Hall said.


"Implementing these models of care would have significant human and financial advantages and could achieve cost benefit ratios of 6.6 times the level of investment needed."

The report looked at how much money could be saved if policies successfully delayed the entry of people with dementia into residential care, by keeping them fitter for longer.

The Framework for Dementia Care referred to by Hall included objectives such as ensuring enough funding so care is not delayed, identifying gaps in dementia care, and supporting workforce training.

The Alzheimers NZ report released tonight estimates there has been a 29 per cent jump in the number of people with dementia over the past five years, from 50,000 in 2011 to 60,000 last year - 1.3 per cent of the population.

Costs have increased from $1 billion to $1.7 billion over the same period, and are forecast to hit $2 billion around 2020, and top $4.6 billion by 2050.

Those estimates include direct healthcare and indirect productivity costs, as well as burden of disease costs. Aged care costs currently account for just over half of dementia-related costs.

Dementia refers to a group of diseases that cause progressive damage to brain cells. Symptoms depend on parts of the brain that are affected, but the most common include changes in memory, thinking, behaviour, personality and emotions.

Dementia is progressive, meaning symptoms get worse over time. Forms of dementia include Alzheimer's disease, vascular dementia, and Lewy body disease.

Age is the greatest risk factor, and others include a lack of physical activity, smoking, excessive alcohol consumption, poor diet and head injuries. While it cannot be cured there is more research into how dementia can be prevented and potentially slowed.

• New Zealand dementia prevalence rate estimates, 2016
0-59 years (0.03 per cent)
60-64 (1.8 per cent)
65-69 (2.8 per cent)
70-74 (4.5 per cent)
75-79 (7.5 per cent)
80-84 (12.5 per cent)
85-89 (20.3 per cent)
90+ (38.3 per cent)
Source: Dementia Economic Impact Report 2016