A new report shows lifestyle risks like smoking, diet and weight are responsible for about 38 per cent of illnesses and premature deaths in Australia.

Fewer Australians are dying prematurely and more could live longer with a healthier lifestyle, a new report says.

The Australian Institute of Health and Welfare report found an 11 per cent decrease in Australia's total disease burden from 2003 to 2015.

The improvement can be attributed to fewer premature deaths from infant and congenital conditions, and fewer deaths from cardiovascular diseases and cancer.

Disease burden is the measure of a population's combined total of years lived with an illness or injury, and years lost to premature death.

The report says 38 per cent of total disease burden could be prevented by reducing lifestyle factors like smoking, obesity, diet and high blood pressure.

In 2015, the total disease burden of tobacco was 9.3 per cent, while obesity and dietary risks contributed to 8.4 per cent and 7.3 per cent respectively.

Cancer, cardiovascular diseases, musculoskeletal conditions, mental and substance use disorders and injuries were the most burdensome illnesses.

The Institute released its report, The Australian Burden of Disease Study: Impact and causes of illness and death in Australia 2015, on Thursday.