Another Australian actor living in Los Angeles has been left to pick up the pieces after his home was destroyed by wildfires raging through the region.

At least five people have been killed but authorities are “nervous about that number” given the level of devastation that one official likened to the aftermath of an atomic bomb.

The fires have consumed nearly 12,500 hectares and incinerated thousands of structures, turning entire neighbourhoods to ash and forcing thousands from their homes.

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Australian Benjamin Rigby is one of the growing number of victims, taking to Instagram with a haunting picture of a fire-damaged staircase leading to where his house once stood.

“My heart is absolutely and completely broken,” he said. “Our home is gone.”

Fellow entertainers were quick to support the actor, writer and producer, who grew up in Queensland and has appeared in Neighbours , Alien: Covenant, Ford v Ferrari and Godzilla vs. Kong.

Melanie Zanetti, who voices Chilli Heeler in Australian megahit television series Bluey, said Rigby was a close pal.

“One of my dearest friends and his partner have lost their house in the LA fires,” she said on Instagram, sharing a link to an online fundraiser set up to help Rigby.

“Anything will help. Love to everyone in LA. Stay safe everyone.”

The Palisades fire between Santa Monica and Malibu on the city’s western flank and the Eaton fire in the east near Pasadena already rank as the most destructive in Los Angeles history.

Aussie actor Vernon Wells spoke earlier this week about the moment he learned he had lost everything in the wildfires.

Close to 180,000 people have been ordered to evacuate their homes, with another 200,000 under evacuation warnings, officials said.

The death toll is likely to rise, Los Angeles Sheriff Robert Luna said.

Luna added it looks as though “an atomic bomb dropped in these areas”.

The Eaton fire alone has damaged or destroyed 4000 to 5000 structures and officials said the Palisades fire destroyed an estimated 1000 more.

The two biggest conflagrations — the Palisades and Eaton fires — formed a pincer around the city so enormous that it was visible from space.

Firefighting crews managed to beat back a third blaze, known as the Sunset fire, which had forced mandatory evacuations in Hollywood and Hollywood Hills — including famous show-business locations such as the TCL Chinese Theatre and the Hollywood Walk of Fame.

The fire was fully contained, Los Angeles Mayor Karen Bass said about midday on Thursday local time.

No buildings were lost in the area and the evacuation order was lifted.

‘Perfect storm’

It was one of at least five separate wildfires burning in Los Angeles County as powerful winds spread flames across parched ground that has seen no rain for months.

Bass described it as a “perfect storm” of dangerous conditions.

President Joe Biden has declared a major disaster in California and met with top administration officials to discuss the federal response.

Firefighters from six other US states were being rushed to California.

- With AAP