South-east Australia has been hit with extreme hot weather, with temperatures of over 40C (104F) in some areas, and several bushfire warnings in place.In Victoria, lightning strikes sparked more than 250 fires on Tuesday night, fire authorities said. A fire ban has been issued across the state.
In Melbourne, a tennis player and a ball boy at the Australian Open collapsed in the heat.
Temperatures in the city remained above 30C for much of Tuesday night.
Country Fire Authority chief officer Euan Ferguson said in a statement: "The extreme temperatures [in Victoria] over the coming three days will test fire services and the community. It's critical we minimise the risk of any fires before Friday."
Road tar melting Firefighters have been able to contain most of the fires in the state, although a number of fires remain out of control.
Emergency fire warnings have been issued for the Victoria communities of Yaapeet and Nypo, with fire authorities urging residents to evacuate due to "a fast moving, out of control bushfire travelling in a south easterly direction".
In 2009, fires in Victoria killed 173 people and destroyed 2,000 homes.
Meanwhile Adelaide, the capital of South Australia, experienced its fourth hottest day on record, reaching 45.1C (107F).
More than 14,000 properties have experienced power cuts, with many thought to be caused by thunderstorms and lightning strikes, ABC reported.
In Tasmania, there were reports of road tar melting in the heat.
At the Australian Open on Tuesday, Canadian tennis player Frank Dancevic collapsed during a match.
He told reporters the heat made him "dizzy" and made him hallucinate.
China's Peng Shuai said the temperatures caused her to vomit during her match. A ball boy also collapsed in a separate match.
Tim Wood, the tournament's chief medical officer, said: "Of course there were a few players who experienced heat-related illness or discomfort, but none required significant medical intervention after they had completed their match."
Bush fires in Western Australia destroyed more than 50 homes earlier this week, the BBC's Jon Donnison in Sydney reports.
Last year was recently declared Australia's hottest on record, further raising questions about the impact of climate change, our correspondent adds.