Australian authorities say an "unprecedented" number of emergency-level bushfires have threatened the state of New South Wales (NSW).
More than 90 blazes were raging across the state on Friday.
The fires - many in drought-affected areas - were being exacerbated by gusty winds and up to 35C heat.
There are reports of people trapped in their homes in several places, with crew unable to reach them due to the strength of the fires.
"We are in uncharted territory," said Rural Fire Service Commissioner Shane Fitzsimmons, with at least 17 blazes at the highest threat level.
"We have never seen this many fires concurrently at emergency warning level."
Authorities warned some people to seek shelter from fires rather than flee, as it was now "too late to leave".
Emergency warnings were also issued on Friday for bushfires burning in Queensland and Western Australia.
In NSW, the worst-hit state, crews have fought hundreds of fires since September. Last month, two people died while trying to protect their home.
The state is in the grip of a long-running drought and authorities warn that many fires will continue to burn unless there is rain.
"We just cannot overstate the profound impact that the drought is having on fire behaviour," Mr Fitzsimmons said.