The number of record hot Australian days has doubled in the past 50 years, with the health system underprepared to deal with escalating heatwaves, a new report has found.

The Climate Council report, released on Wednesday, found nursing homes and medical centres across the country may not be equipped with necessary back-up energy and water supplies in extreme heat.

It found heatwaves were getting longer, hotter and more intense and have caused more deaths since 1890 than bushfires, cyclones, earthquakes, floods and severe storms combined.

The council noted several states had upgraded heat and health warning systems since the deadly heatwaves in 2009, but the lack of a streamlined response system was putting lives at risk.

Professor Lesley Hughes, who will chair a health professional extreme heat summit next week, says hundreds of people could die each year by 2050 if nothing is done to tackle climate change.

"Reducing greenhouse gas emissions rapidly and deeply is the only way to protect Australians from worsening extreme heat events," she said.

The report found heatwaves put pressure on health services, with emergency call-outs jumping almost 50 per cent and heart attacks almost tripling in the heatwaves of January and February 2009.

Extreme heat can cause dehydration and heat stroke which puts stress on organs and can trigger fatal illnesses like cardiac arrest.

Elderly Australians and babies, the homeless and people in lower socio-economic areas without access to air conditioning are most at risk of serious injury or death.

The report highlights the global problem of heatwaves, pointing to 55,700 deaths during the Russian heatwave in 2010, and 3700 killed in India and Pakistan in May 2015.

By 2030, Australia's annual average temperature is predicted to rise by 0.6 to 1.3 per cent, with the globe continuing to heat up to the end of the century, the report said.

"Australia is already experiencing and can expect more frequent and intense heatwaves because of climate change," the report said.

Last year, 197 parties signed on to an international climate change deal to limit global warming to two degrees by 2100.