The team compared the climate models used by the Intergovernmental Panel on Climate Change (IPCC) and tested their accuracy against actual climate observations to select the strongest and weakest ones.
The researchers looked specifically at rare extreme events - those that occur on average once each 20 years - because heatwave conditions can dramatically affect biological, physical or human systems and are of most concern for planners and policy makers.
They found that the best-performing climate models simulated smaller rises in the temperature extremes compared with the models that performed poorly.
The study's authors caution that this is not good news: the increases in the extreme temperatures predicted by the strongest models are still extremely high and would generate heat waves much worse than the recent one that hit south-eastern Australia, they say.
The study was authored by Sarah Perkins, Professor Pitman - both of the UNSW Climate Change Research Centre- and Dr Scott Sisson, UNSW School of Mathematics and Statistics.
For a more detailed view of this study, please see: