About 500,000 Australians have heart valve disease, but many cases go undiagnosed.

Cardiologists are asking Australians over 65 to get checked for heart valve disease next time they visit their GP.

"We think half a million people have heart valve disease, but only half realise they have it," the Chief Executive of the Baker Institute, Professor Tom Marwick, told AAP.

He said older Australians who find they can't exercise as much often put it down to ageing, without realising it could be one of the first symptoms of the illness.

"This is a fixable problem, the frustrating thing is when it's recognised late, people already have heart damage," he said.

Heart valves are very small pieces of tissue that acts as doors to the heart's chambers.

If they leak or grow narrow, this can disrupt the organ's blood flow, leading to rhythm disorders and blood clots, even progressing to heart failure.

Prof Marwick wants GPs and policymakers to be made aware the disease is increasingly common due to the ageing population.

In the past, it was linked to rheumatic fever, an illness still detected in aboriginal Australians despite being rare in the rest of the population.

But Prof Marwick said surgery to fix it is now much simpler, thanks to valves that can be delivered via catheter.

The Baker Institute on Monday released a white paper that warns the disease can go unrecognised, undiagnosed and untreated.