Australia's record heatwave has sparked a series of wildfires currently burning out of control and raised fears of a climate future dominated by bushfires.

The mercury in Sydney, the largest city of Australia's most populous state of New South Wales (NSW), topped 43 degrees Celsius by 3 pm.on Tuesday. The Bureau of Meteorology has described it as the third hottest day on record.

While Police on the southern island of Tasmania continue to search for the missing after a week of wildfires, Australian Prime Minister Julia Gillard toured the destruction site near Hobart, warning Australians of a future of bushfire fighting as global warming continues.

Dr. Philip Gibbons, at the Australian National University's Fenner School of Environment and Society, told Xinhua that Australia may have to brace for an increase in these devastating fires as the world's warming continues to accelerate.

"Australian flora and fauna have adapted over millennia to bushfires during the hot Australian summer. Indeed, some Australian plants and animals depend on fire."Dr Gibbons said.

"However, more days of extreme to catastrophic fire danger are predicted to occur in southern Australia with climate change -- and we may already be witnessing this.

"This will result in more frequent bushfires, will result in wetter habitats like rainforest becoming more fire prone and will result in greater amounts of vegetation clearing to reduce fuels," he said.

Prime Minister Gillard agreed, telling local media of the likelihood of further "catastrophic" days.

"We do know over time that as a result of climate change, we are going to see more extreme weather events and conditions." She said.

More than 100 fires were burning across NSW at 3 pm (EST), 20 of which have been described as out of control, mainly in south of Sydney and in forested federal territory around Canberra, Australia's inland capital.

Thousands of firefighters and about 70 aircraft have been put on standby.NSW rural fire service commissioner Shane Fitzsimmons urged residents to prepare for "awful conditions," with humidity at only 10 percent and winds gusting over 70 kilometers per hour.

Temperatures across the country have skyrocketed with gale-like winds fueling the bushfires with officials deeming over 90 percent of the state declared in either"severe" or "catastrophic" danger.

NSW Emergency Services Minister Mike Gallagher said the worst predictions of "catastrophic weather was now starting to play out".

"There was a hope that something would abate this weather condition as it moves across NSW, but the fact is that it has not, "he told reporters in Sydney.

NSW Rural Fire Service Commissioner Shane Fitzsimmons told reporters that the day would be one of the longest for the thousands of firefighters prepped for battle.

"Right across the state we are seeing fires breaching some of their containment lines, and we've also got fire agencies identifying new fires that are starting up under these hot, dry conditions.. We've got a lot of daylight left and a lot of nighttime left under these conditions,"he said.

Two crews of firefighters from New Zealand have been asked to assist in Tasmania, where some 100 homes and properties have been gutted by fire in the last seven days.

However, according to Fire Services, the worst may be yet to come.