A new report shows that walking just an extra 15 minutes a day could significantly reduce the risk of disease.

Australians have been warned against underestimating the impact of inactivity on their health, with a new report showing walking just an extra 15 minutes a day could significantly reduce their risk of disease.

Released by the Australian Institute of Health and Welfare on Wednesday, the report shows 2.6 per cent of the total disease burden in Australia was due to physical inactivity.

When physical inactivity was combined with the incidence of overweight and obesity the burden increased to nine per cent.

But the impact could be significantly reduced with just small changes to levels of physical activity at a population level.

'We found that if everyone did an extra 15 minutes of brisk walking, five days each week, this would reduce disease burden due to physical inactivity in the population by about 13 per cent," said AIHW spokesperson Michelle Gourley.

The report looks at the health impact of a lack of physical activity, both in terms of years of healthy life lost through living with an illness or injury, and through dying prematurely.

Using data from 2011, the analysis found inactivity was associated with seven diseases.

The disease most closely linked to physical inactivity was diabetes - for which physical inactivity was responsible for 19 per cent of the burden.

Bowel and uterine cancer combined and dementia were the next top three diseases closely linked to sedentary behaviour, accounting for 16 per cent and 14 per cent of the physical inactivity burden.

Being inactive also had a strong link with heart disease. One-third of the total burden due to physical inactivity in Australia was caused by heart disease.

Heart Foundation National CEO John Kelly says people should not underestimated the impact of physical inactivity on their health.

"Walking is hugely underrated as a powerful prescription for good health and this latest research shows how beneficial it can be in lowering your risk of heart disease," he said.

Simple ways to add extra steps to a person's day include talking a walk at lunch, getting off the bus or train a few stops earlier, or parking a few blocks away from the office, advised Mr Kelly.

A Breakdown of the Burden of Physical Inactivity on Disease

* Diabetes - inactivity responsible for 19 per cent
* Bowel & Uterine Cancer - inactivity responsible for 16 per cent
* Dementia - inactivity responsible for 14 per cent
* Breast Cancer - inactivity responsible for 11 per cent
* Coronary Heart Disease - inactivity responsible for 11 per cent
* Stroke - inactivity responsible for 10 per cent