The set of Australian soap opera Home and Away has been seriously damaged by the bushfires raging outside Sydney.

Thousands of firefighters have been battling the 70 blazes threatening suburban homes since Wednesday and caused by searing summer temperatures.

Flames swept through the Jackaroo Ranch at Annangrove, north west of the city, where Seven Network has filmed many of the soap's scenes for the past 15 years.

Executive producer John Holmes said the caravan park, run by the show's Fletcher family, had suffered most.

"Apparently, there's nothing remaining of the caravan park," said Mr Holmes.

The fires are the worst in 30 years

"The house is a stone house, but the roof had collapsed and parts of the wall and some of the veranda had all gone."

Home and Away, which is shown on Five in the UK, takes place in the fictional hamlet of Summer Bay with the action mainly taking place in the diner, on the beach and at the caravan park.

Global audience

No one was hurt in the fires but the park will have to be rebuilt and all the caravans replaced.

However, viewers are not expected to see any disruption as the series is filmed around four months in advance.

Elsewhere around Sydney, more than 20 houses have been destroyed as conditions deteriorate rapidly.

High winds have been fanning the flames tearing through the bone-dry bush land.

Home and Away began in 1988 and was developed by Seven after the network dropped Neighbours because of poor ratings.

But Neighbours was picked up by the rival Network Ten and became an international success.

In the UK, ITV began screening Home and Away in 1989 to counter the BBC's success with Neighbours.

But the series was poached by Five, which began showing it in July 2001.

Home and Away is shown in about 50 countries is thought to have a global audience of about 60 million viewers.