The number of people in Northern Ireland with dementia is expected to double in the next 20 years.
About 19,000 people are currently living with the condition, but that figure is expected to rise dramatically as people live longer.
Dr Peter Passmore, professor of ageing and geriatric medicine at Queen's University Belfast, said it was an incurable disease.
But he said that people must begin to address it.
"Dementia is an evil, wicked and incurable disease," he said.
"It is a disorder of the brain that causes brain failure. At the moment, it isn't treatable and is one of the most costly diseases we have to deal with."
Figures for last year show that dementia cost the UK health service around £23bn. That is nearly as much as cancer, stroke and heart disease combined.
Dr Passmore said that because more people were living longer that cost would rise considerably unless something is done about it now.
"I think the first thing to do from a family perspective is to try and broach the subject very carefully," he said.
"The individual may have already realised, but a tactful approach from others, especially family, should be the first port of call.
"People do admit there is a problem and agree to treatment - that's the philosophy of a majority of people who attend my clinic at the Belfast City Hospital. "
Dementia is an umbrella term used to refer to a collection of symptoms that can result from a number of different diseases of the brain. Those symptoms include a decline in memory, reasoning and communication skills and a gradual inability to carry out everyday activities.
There are many different types of dementia but they all affect the way the brain works and therefore have a massive impact on the quality of a person's life.
Dr Passmore said dementia is a complex condition that is often difficult to diagnose.
"The most obvious thing is that the brain can shrink a little - the other changes can only be detected under a microscope.
"With Alzheimer's, it is lots of proteins that clump together to form what we call plaques - these aren't normal. Then, within those cells, there is a series of tangles that have to do with the way the energy and cells move around. When they don't move about normally, it affects how a person thinks and how quickly they react."
There is growing momentum among experts that there must be greater awareness of the condition and that the public should be armed with more information.
The director of the Dementia Services Development Centre in Scotland, Professor June Andrews, said that while figures are an estimate, the number of those who have the condition is likely to double and people need to be prepared.
"The most important thing is information - knowing how to keep yourself well; knowing when to go to the doctor; knowing what changes to make to your home; knowing where to seek help," she said.
"All of these things help prevention and that keeps people out of care which is a good thing."
Her research at the University of Stirling looks at how people can make their homes more adaptable. In most cases, this increases the time they can enjoy living independently.
"Simple things can make a huge difference to someone with dementia - like more light in a home, having things colour co-ordinated or by using pictures.
"Having glass-fronted units so people can see items clearly and quickly cuts down on the confusion and sense of frustration.
"There is no reason why people have to stop using a kitchen - it just needs to be better planned. For instance you can get cookers with cut-out mechanisms.
"Also, entice people with dementia to eat by installing a glass fronted fridge which is organised and clear, with food prepared."
Professor Andrews said the cost of design changes to the home compared to that of placing someone in residential care is massive and should be explored.
"It all adds up. First there is the cost to families and, through social care services, at home. Then there is the huge cost of hospital and care home care.
"With the numbers increasing, we need to do dementia care better, and the best way is to give people the information they need to look after themselves and avoid the common problems," she said.