Since 2006 teams of researchers across the country have been studying more than 1100 Australians at regular intervals, collecting data they hope will pinpoint lifestyle and health factors that lead to Alzheimer's disease.

Dementia, of which Alzheimer's disease accounts for around 60 per cent of all cases, is the single biggest cause of disability in older Australians, costing the nation at least $4.9 billion a year in direct health and aged care. Around 1.13 million Australians are expected to be suffering dementia by 2050.

Using data from the Australian Imaging, Biomarker and Lifestyle study of ageing, researchers have been able to detect key build-ups in the brain, known as amyloid plaques, years before patients begin to show any signs of dementia.

If detected early enough, patients in clinical trials can begin taking preventative medication that it is hoped will help clear those build-ups before they cause damage to cells, similar to the way cholesterol drugs can help clear build-ups in arteries.

But unless extra funds can be found the AIBL study is expected to run out of money in less than 12 months, placing in jeopardy the data that researchers are relying on.

Current Alzheimer's tests are expensive and involve injecting patients with radioactive tracers and placing them in a Positron Emission Tomography scanner.

Director of nuclear medicine at Austin Health in Melbourne Professor Chris Rowe and his team have been using the AIBL data to develop a cheaper blood test that could be used to identify members of the public likely to develop Alzheimer's disease and, hopefully, intervene to prevent or significantly delay onset.

"We've had some promising early results, but our research depends very heavily on the AIBL study, and that study has now run out of money," Professor Rowe said.

"We've got all the blood results and other data going back, it's highly regarded as probably the best longitudinal study of its kind in the world and it will be a major tragedy if it folds up due to lack of local funding."

The Federal Government pledged an additional $200 million over five years towards dementia research in the last budget, but the study may run out of funds before that money becomes available and there were no guarantees it would be successful in accessing a grant.

The National Health and Medical Research Council has begun assessing bids for that funding, and senior deputy director of mental health at the Florey Institute Professor Colin Masters said there were high hopes but no guarantee the AIBL study could be saved.

"These things take time to roll out and at the moment we've got clear problems with bridging now and whenever other funds may flow."

"Right now it is starting to pay dividends in that we can identify people in the preclinical stages before the onset of any impairment. These are the individuals who are potentially eligible for clinical trials that will show us the way forward for delaying the onset of Alzheimer's," Professor Masters said.

"We're beginning to build up a database where we really understand the evolution of the disease."

In addition to the multibillion-dollar potential savings to the health system, the blood test could also generate significant revenue for Australia if commercialised, with the number of dementia cases worldwide expected to triple to 115 million by 2050.

Work on the blood test has already attracted the interest of the US military which has spent close to $1 million funding Australian studies involving war veterans that are also examining links between head trauma, post-traumatic stress disorder, and dementia.

Alzheimer's Australia national general manager of research Dr Chris Hatherly said there would be significant benefits to funding the study for a further five to 10 years if it was possible.

"I would hope the AIBL study will have a good hearing when the priorities for that funding are determined early next year.

"It's a struggle for AIBL as it is for every research project to access funding but AIBL has been fairly successful in accessing foreign investment, so the researchers can hopefully find other ways to cobble funding together to keep the research going," he said.