"The current heat wave is unusual due to its extent, with more than 70 percent of the continent currently experiencing heat wave conditions," John Nairn, South Australia's acting regional director for the Bureau of Meteorology, told the Australian Science Media Center.
Forecast temperatures for Australia are so extreme that the bureau has added a new color -- purple --- to its temperature scale, increasing the previous cap of 120 degrees Fahrenheit to 129 degrees.
The bureau said portion of central Australia could see temperatures on excess of 120 degrees next week. The all-time record high in Australia is 123 degrees set in 1960.
"This event is ongoing with significant records likely to be set," a bureau statement said, The Sydney Morning Herald reports.
The Australian Broadcasting Corp. reported Tuesday that more than 140 fires continued to burn in sweltering conditions across New South Wales.
"It's shaping up to be a very difficult day. You don't get conditions worse than this," said NSW Rural Fire Service Commissioner Shane Fitzsimmons, who said at a news conference that the crisis had reached a "catastrophic level."
Australia has faced a stream of erratic weather. In 2011, the state of Queensland was hit by flooding and cyclones, and last year a decade-long drought that had affected the country's farms was declared over. Firestorms in 2009 claimed hundreds of lives.
Just for the first seven days of 2013, six were among the top 20 hottest days in the past century and the last four months of 2012 were the hottest on record for Australia.
Australian Prime Minister Julia Gillard didn't rule out climate change as the root of the country's weather challenges.
Noting that "we live in a country that is hot and dry and where we sustain very destructive fires periodically," Gillard told reporters Monday, "Whilst you would not put any one event down to climate change, weather doesn't work like that, we do know over time that as a result of climate change we are going to see more extreme weather events and conditions."
The Intergovernmental Panel on Climate Change, in a recent assessment of the effects of climate change, predicted that in south-eastern Australia, the frequency of days in which extreme fire danger is a threat will increase by up to 25 percent by 2020, and up to 70 percent by 2050.
In its most recent study of the impact of climate change, Australia's Bureau of Meteorology said that average temperatures across the country have increased by almost 1.8 degrees Fahrenheit since 1910 and could rise 9 degrees Fahrenheit by 2070.