A bushfire rages in the Sydney suburb of Londonderry as firefighters battle to contain the blaze.

A severe weather warning for damaging winds is threatening to hamper Australian firefighters battling an out-of-control bushfire in Sydney's west that is threatening "dozens" of homes.

On Sunday afternoon, the Rural Fire Service renewed a warning to residents in the suburbs of Londonderry, Llandilo and Berkshire Park that it was too late to leave and to take shelter in their homes.

The fire has grown to almost 300 hectares in size and is burning between The Northern Road, Stony Creek Road and Ninth Avenue.

SYDNEY MORNING HERALD Firefighters face strong winds fanning an out of control fire in Sydney's west.

Dozens of homes remain under threat around the perimeter.

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The Bureau of Meteorology is forecasting wind gusts in excess of 90km/h in the Southern and Central Tablelands on Sunday night.

CHANNEL 7 The bushfire threatening nearby homes on Sunday.

At 3pm (Australian time), westerly winds were gusting at 63km/h in nearby Penrith.

RFS deputy commissioner Rob Rogers told Channel Nine it was a "very volatile situation".

SYDNEY MORNING HERALD Thick black smoke erupts from the out of control bushfire.

Strong winds remain the major concern, causing spot fires to jump ahead of the main blaze, with embers threatening to ignite more spot fires.

But the RFS is confident it has all the resources on the ground and in the air to combat the blaze.

BUSHFIRE EMERGENCY: McDonnell Douglas DC-10 VLAT brought in to help tackle an out-of-control bushfire at Londonderry and Llandilo. #9News pic.twitter.com/1yf7lBLGaQ — Nine News Sydney (@9NewsSyd) November 13, 2016

Hundreds of firefighters are battling the flames and several heavy-duty water bombing aircraft - including the Hercules C130, known as Thor, and the McDonnell Douglas DC-10, known as VLAT - are helping to douse the flames.

Jordan Springs resident Melinda Eliassen told Fairfax Media the fire spread quickly and is "getting worse".

"There are clouds of black smoke," Eliassen said. "It's just getting blacker and blacker."

BUSHFIRE EMERGENCY: The Skycrane has been called in as @NSWRFS crews battle an out-of-control bushfire at Londonderry. #9News pic.twitter.com/LjcJZhBRiK — Nine News Sydney (@9NewsSyd) November 13, 2016

The fire started on The Northern Road in Londonderry and jumped across into the Castlereagh Nature Reserve, the spokesman said. The cause of the fire will be investigated.

A very high fire danger rating was issued for the Greater Sydney region for Sunday because of warm and windy weather.