A vast area of Australia’s east coast, including parts of the Sydney suburbs, is facing one of the nation’s worst-ever bushfire threats.

More than 85 fires are burning across the state of New South Wales (NSW), 46 of which are not contained.

Authorities had predicted “catastrophic” conditions for Tuesday, amid fears a southerly wind could cause the flames to change direction.

About six million people live in the region.

Firefighting planes dropped flame retardant over trees and homes in the suburb of South Turramurra, on Sydney’s north shore, as the bushfires came within 15km (nine miles) of the city centre.

Authorities said the Turramurra fire had been brought under control, but one firefighter battling the blaze there had suffered a broken arm and suspected fractured ribs.

State Premier Gladys Berejiklian, who has declared a seven-day state of emergency, said Tuesday would be “about protecting life, protecting property and ensuring everybody is safe as possible”.

People in vulnerable NSW communities have been urged to stay away from bushland, and to flee their homes before the fires escalate. More than 600 schools are closed across the state.

How bad are the fires?

Three people have died and more than 150 properties have been destroyed since the fire emergency intensified in NSW on Friday.

But authorities said they were now facing what could be “the most dangerous bushfire week this nation has ever seen”.

There are 14 fires burning at emergency level across the state.

Experts have compared Tuesday’s forecast to the 2009 Black Saturday bushfires in Victoria, when 173 people died.

It’s the first time that a “catastrophic” level fire warning has been in place across the greater Sydney area and in the regions to the city’s north and south. The highest level rating was brought in after the 2009 disaster.

“Under catastrophic conditions, fires that start and take hold will grow and develop extremely quickly and become large fires very, very easily,” Commissioner Shane Fitzsimmons said.