A postgraduate science student says she's been discriminated against because she has a diagnosis of dementia.

When Juanita Hughes was diagnosed with dementia at the age of 54, people "wrote her off", she says, including members of her own family.

Two years on, she is studying for a Master of Diagnostic Genomics, and planning to get a PhD.

But in August, a neurologist told her she had to give up her driver's licence without checking whether she could actually drive, Ms Hughes told AAP.

"It came as such a shock, it was the last thing I expected ... I think it's extremely discriminatory."

Ms Hughes says she can drive and plans to fight the doctor's ban.

She believes it's an example of widespread prejudice faced by people diagnosed with dementia, an umbrella term for a number of conditions that impair brain function.

Frontotemporal dementia runs in Ms Hughes' family - her grandfather, great uncle, father, uncles, and a sister also have the disease.

"Our family is rife with it," she said.

She says the treatment of people who've been diagnosed is unfair, but there are other problems too.

"Just as bad is people who look at you and if you sound intelligent they won't believe you have dementia, and that is very insulting," she said.

About nine in ten people living with dementia feel patronised, and treated as though they are not smart, according to research by Dementia Australia.

The survey of about 1000 people found roughly the same number said that after they were diagnosed, people didn't keep in touch with them as much.

Dementia Australia chief executive Maree McCabe said discrimination can lead to isolation, loneliness and poor mental health - experiences intensified by the pandemic.

"We need to shift our thinking around dementia to stop adding discrimination to the symptoms that people with dementia experience," she said in releasing the report on Monday.

Meanwhile a snapshot of dementia in Australia shows the number of people living with the disease is continuing to rise.

The Australian Institute of Health and Welfare report released on Monday shows dementia is the second leading cause of death in Australia, with almost 500,000 people suffering from the disease.

That number is expected to increase to about 850,000 over the next four decades.

In 2019 dementia was responsible for about 14,700 deaths, just under ten per cent of all deaths in that year.

Dementia Action Week is from September 20-26 and Tuesday September 21 is World Alzheimer's Day.