SYDNEY - While the eastern United States remained locked in a record deep freeze, southeast Australia wilted under scorching heat, with temperatures across Sydney hitting in excess of 40 degrees Celsius on Sunday (Jan 7).

Penrith in western Sydney hit 47.3 deg C, the highest temperature there since 1939 and just shy of the all-time record for Penrith of 47.8. Sydney's central business district reached 43.4 deg C, the Sydney Morning Herald reported. Parts of Sydney are forecast to reach 40 deg C on Monday, the Bureau of Meteorology said.

Sydneysiders headed for the beach, lakes and rivers to beat heat while matches at an international tennis tournament in the city were cancelled because of extreme temperatures.

Mission Australia's homeless transport service Missionbeat were out in force to keep people cool, Australia Broadcasting Corp reported, helping take heat-affected homeless people to hospital or to refuges and hostels.

Animals at Taronga Zoo on Sydney's north shore were also fed a variety of iced foods to keep them cool, ABC said.

The heatwave affected much of southeast Australia over the weekend with some inland areas hitting 45 deg C.

Extreme heat and fire risk warnings were issued for Victoria, South Australia, New South Wales and Tasmania, though temperatures eased on Sunday afternoon after a cool change swept through.

On Saturday, bushfires broke out in Victoria and South Australia, including a fire that burned several structures on the outskirts of Melbourne.

About 400 homes lost power and 50 fires were reported across Victoria on Saturday, although many were small and were extinguished, Reuters reported.

Emergency warnings were issued both in Victoria and South Australia, with authorities warning of catastrophic fire conditions.

The heat was strong enough to melt the bitumen on a 10km stretch of freeway in Victoria, national broadcaster ABC News reported on Saturday.

Australia is prone to deadly blazes, thanks to its combination of remote terrain, high summer temperatures and flammable eucalyptus bush.

In 2009, the worst bushfires on record destroyed thousands of homes in Victoria, killing 173 people and injuring 414 on a day the media dubbed "Black Saturday".