A new report has revealed osteoporosis is being under-diagnosed in Australia and it is costing taxpayers.

Bone health has been put on the map following a new report into preventing and diagnosing osteoporosis.

Former Australian cricket captain Michael Clarke and Olympic champion hurdler Sally Pearson are helping deliver the message as ambassadors after launching the report in Canberra.

Osteoporosis Australia chief executive Greg Lyubomirsky said too many people, younger and older, were breaking bones.

More than five million Australians older than 50 have poor bone health, while the cost to the health system of broken bones was around $1 billion last year.

"In Australia, osteoporosis is under-diagnosed and under-treated," Mr Lyubomirsky said.

"In people aged over 50, osteoporosis is the most common cause of fractures yet in only 20 per cent of these fractures patients are being investigated for osteoporosis.

"Most patients are not being diagnosed, and remain unaware of their underlying health issue."

The launch of the Know Your Bones risk report, a joint initiative by Osteoporosis Australia and the Garvan Institute, coincides with World Osteoporosis Day on Thursday.