Australia's blistering heatwaves kill many more people than any other natural hazard, and more can be done to prepare for future events, new research says.

Hospital emergency and ambulance demand, as well as mortality, increases significantly during heatwaves, research from James Cook University shows.

The report examines a growing number of recorded heatwaves and extreme heat events between 2000 and 2020.

"Australia has experienced a consistent increase in amplitude, magnitude, frequency and duration of heatwaves, which have been attributed to the effects of climate change," JCU's associate lecturer and lead author Hannah Mason said.

The study found that during heatwaves there was a notable increase in hospital admissions for cardiovascular, renal, respiratory, mental and behavioural conditions.

"Direct effects of heat, such as heat stroke, dehydration, organ failure and cardiac arrest can be exacerbated for people with pre-existing medical conditions," Miss Mason said.

The study found the most common risk factor during heatwaves was for people aged over 60 and under 18, as well as those of low socio-economic status.

Health services are also directly impacted by heatwaves through the effects on staff, power and water consumption and other infrastructure and mechanical failures, the study found.

"With the likelihood of increasing heatwaves and their severity, early warning systems and preparedness programs, especially for health services, should be developed and evaluated to address areas where we anticipate more demand during heatwaves," said report co-author Professor Richard Franklin.

"Health planning is essential at the community, state and federal levels to mitigate the impacts of these events on health and health service delivery, especially for vulnerable populations,"

The research is part of a wider study to improve the understanding and reduce the impacts of heatwaves on health.