Australian heatwaves are hotter and longer, climate study finds

Heatwaves in Australia are becoming more frequent, are increasing in intensity and are lasting longer, according to an interim report by the Climate Council.

The report finds that climate change is having a key influence on a trend that has seen the number of hot days in Australia double and the duration and frequency of heatwaves increase between 1971 and 2008.

South-eastern Australia has baked in extreme temperatures this week, with Melbourne experiencing four consecutive days over 40 degrees celsius - a run not replicated since 1908. Adelaide went one further and had six days over 40.

Dozens of wildfires are burning out of control. Fire authorities say 68 fires were burning across Victoria yesterday and 16 were blazing across South Australia. One person died of "fire-related" causes in the Grampians, northwest of Melbourne.

The Climate Council, a privately run group of climate scientists and economists who previously formed the government-funded Climate Commission, defines a heatwave to be at least three consecutive days at a temperature in the top 10 per cent for that time of year.

Its interim report states there will still be record cold events but that these events are being eclipsed by record hot events by a ratio of three to one. Heatwave frequency in Australia will "increase significantly", it warns.