Dozens of homes destroyed as out-of-control wildfire rages on outskirts of Perth, Australia

An out-of-control wildfire burning north-east of the Australian west coast city of Perth has destroyed an estimated 30 homes and is threatening more, with many locals in the region told it is too late to leave.

The 7,000-hectare blaze, which has a 47-mile perimeter, began on Monday and raged through the night near the town of Wooroloo, with the shires of Mundaring, Chittering, Northam, and the city of Swan impacted.

Swan mayor Kevin Bailey said more than 30 homes are believed to have been destroyed.

"We are just waiting for confirmation of the numbers but we're looking somewhere in the vicinity of 30-plus homes lost," Mr Bailey said.

He said one firefighter had been treated for smoke inhalation. There had been no other injuries.

Western Australia's Department of Fire and Emergency Services deputy commissioner, Craig Waters, said the fire had doubled in size overnight and burned through 7,366 hectares of farm and woodland.

"Strong winds are hampering us getting in and containing the fire and bringing it under control," he said.

State premier Mark McGowan said 80 per cent of all properties near Gidgegannup on Perth's north-east rural fringe have been lost.

Firefighters will investigate whether there has been any loss of life, he said.

Mr McGowan said a large aerial tanker was flying from the Australian east coast to help fight the blaze.

"This is an extremely dangerous fire and a serious situation. Weather conditions are extremely volatile," Mr McGowan said.

"Please do everything you can to keep you and your family safe and look after each other," he added.

People in a 16-mile stretch west from Wooroloo to the Walyunga National Park north-east of Perth had been told on Tuesday it had become too dangerous to leave their homes.

"You must shelter before the fire arrives, as the extreme heat will kill you well before the flames reach you," the latest warning said.

Roads out of semi-rural suburb The Vines on Perth's northern outskirts were bumper-to-bumper with traffic, making some people choose to stay.