In Brisbane on Wednesday, Mr Truss acknowledged the record heatwave, but said Australia's climate was changeable, with hot times and cold times.

''The reality is, it's being utterly simplistic to suggest that we have these fires because of climate change,'' he said. ''It's too simplistic to link one hot spell to climate change.''

Earlier this week, when touring fire-affected areas of Tasmania, Prime Minister Julia Gillard linked extreme weather events to climate change. She said: ''While you would not put any one event down to climate change … we do know that over time as a result of climate change we are going to see more extreme-weather events.''

As Fairfax Media reported on Wednesday, the Bureau of Meteorology says this heatwave - in terms of its duration, intensity and extent - is unprecedented in its records.

Mr Truss is acting Opposition Leader as Tony Abbott has been deployed to Nowra, New South Wales, as a volunteer with his local fire brigade. Mr Abbott has delayed his annual holiday by three days to help the Davidson Rural Fire Brigade.

He spent Wednesday morning at Deans Gap, where he was spotted driving a fire truck.

Mr Abbott has been a volunteer with his local fire brigade since 2000. ''I urge all people living in areas facing fire risk at this time to monitor emergency messages carefully, activate their fire plans and stay safe,'' he said in a statement.