Climate change should be recorded as a cause of death on death certificates in Australia because heat-related mortality is so vastly unreported, according to commentary published in The Lancet Planetary Health on Thursday.

Over the past 11 years in Australia, just 340 deaths have been recorded as being caused by excessive heat, but statistical analysis by two doctors with the Australian National University shows that 36,765 could have been attributed to heat.

"Climate change is a killer, but we don’t acknowledge it on death certificates," co-author Arnagretta Hunter, from the ANU Medical School, said.

She said it was acknowledged that phenomena caused or exacerbated by climate change - such as drought, bushfires, floods and storms - had an impact on illness and death rates in Australia, but that there was no way to acknowledge these factors on death certificates.