Australian Prime Minister Scott Morrison on Saturday called up 3,000 defence force reservists as the threat of wildfires escalated on what shaped as a torrid weekend in at least three states.
As temperatures in western Sydney reached 47 degrees Celsius, Mr Morrison said two more deaths had been confirmed on Saturday, bringing the toll since the country's worst wildfire season on record began in September to 23.
"We are facing another extremely difficult next 24 hours," Mr Morrison told reporters, while also confirming his scheduled visits to India and Japan later this month had been postponed due to the ongoing situation.
Australia was bracing for one of the worst days of the crisis yet on Saturday, as searing heat and strong winds were forecast to bring flames to more populated areas.
Officials warned a fire in a national park west of Sydney had the potential to spread into the city's outer western suburbs.
The defence force reservists will fight fires alongside thousands of full-time and volunteer firefighters, plus scores more brought in from other countries including Canada and the United States.
New South Wales Premier Gladys Berejiklian says her state is facing "another terrible day" and called on people in areas threatened by the fires to leave while they still could.
Authorities also repeated warnings fires could move "frighteningly quick", with embers carried by wind having the potential to spark new fires or enlarge existing ones.
Australian navy ships have been lifting hundreds of people from beaches in towns cut off by roads by the fires.
Tens of thousands of people have been urged to flee communities near fires, many of them coastal holiday centres, before hot and windy weather intensified over the weekend.
At midnight there are still 137 fires burning across NSW with over 60 yet to be contained.Over 2000 firefighters are continuing to work hard throughout this evening in preparation for Severe and Extreme Fire Danger predicted for many parts of the State today.#NSWRFS#NSWFirespic.twitter.com/Bxv1ILtt6v
— NSW RFS (@NSWRFS) January 3, 2020
Australia's summer wildfire season arrived early – in September – and has been more intense than any on record.
Collectively, more than 20,000 square miles has been burnt out around the country, and area almost the size of Croatia.
At least 20 people have died, and more than 1,400 homes have been destroyed.