David Cameron is set to announce that funding for research into dementia will be doubled to £66m by 2015.
Dementia is thought to affect around 800,000 people in the UK and the prime minister is expected to say in a speech that the level of diagnosis, understanding and awareness of dementia is "shockingly low".
"One of the greatest challenges of our time is what I'd call the quiet crisis,” Cameron will say. “One that steals lives and tears at the hearts of families, but that relative to its impact is hardly acknowledged.
"Dementia is simply a terrible disease. And it is a scandal that we as a country haven't kept pace with it.”
The prime minister will say that the costs associated with the disease are already higher than those for cancer, heart disease or stroke.
"So my argument today is that we've got to treat this like the national crisis it is. We need an all-out fightback against this disease, one that cuts across society.
"That ambition - nothing less than for Britain to be a world leader in dementia research and care."
Funding for research in 2010 totalled £26.6m and under the plan it will increase to £66m by 2015.