The long-awaited national climate risk assessment found that rising temperatures will have "cascading, compounding, concurrent" impacts on life in Australia, home to more than 27 million people.

"We are living climate change now. It's no longer a forecast, a projection or prediction -- it is a live reality, and it's too late to avoid any impacts," Climate Minister Chris Bowen said.

The report, prepared independently for the government, found that 1.5 million people living in coastal areas will be at risk of sea level rise by 2050.

By 2090, about three million people will be at risk from rising oceans.

Losses in Australian property values are estimated to soar to Aus$611 billion (US$406 billion) by 2050 and could increase to $770 billion by 2090.

Should the temperatures increase by 3C, heat-related deaths could soar by over 400 percent in the country's most-populated city of Sydney, the report said.

One of the world's biggest fossil fuel exporters, Australia has been criticised for treating climate action as a political and economic liability.

The centre-left Labor government has stepped up efforts in recent years to bring down emissions and roll out renewable energy.

Monday's report comes as Australia is set to release its next round of emissions reduction targets in the coming week, a key obligation under the landmark Paris climate agreement.

Many hope the sun-kissed country will reveal more ambitious targets.