SYDNEY, May 21 (Xinhua) -- Australia's average life expectancy is under pressure from rising obesity rates, a study by the University of Melbourne has showed.

After increasing rapidly for 20 years, the growth rate of Australian's life expectancy has fallen behind most other high-income countries.

"There are several major barriers to marked increases, including the notably higher mortality of more recent birth cohorts and the comparative failure of efforts to reduce levels of overweight and obesity," University of Melbourne researcher and co-author Tim Adair said.

Between 1981 and 2003, the difference in life expectancy between males in Australia and other high-income countries increased from +0.7 years to +2.3 years, while for females the difference in life expectancy increased from +0.9 years to +1.3 years.

However by 2015 that growth had slowed for both sexes compared to most other high-income countries. For males it was +2.3 years, and for females +1.1 years.

"Life expectancy in Australia is among the highest in the world, a testament to boldly progressive public health interventions over several decades," Adair said.

Adair said that unless new strategies for reducing mortality associated with specific behaviors are developed and deployed effectively, the country's high global life expectancy rating is unlikely to persist.