Warnings: 90km/h Wind Whips Up Fast Moving NSW Fire

Stronger-than-expected winds are whipping up a fast-moving bushfire in the NSW Hunter, putting dozens of homes near Newcastle airport under threat.

Stronger-than-expected winds are whipping up a fast-moving bushfire in the NSW Hunter, putting dozens of homes near Newcastle airport under threat.

An emergency warning was re-issued on Friday morning after the blaze at Campvale flared up just after sunrise and headed towards Rookes Road in Salt Ash.

It's believed two sheds have already been destroyed by the fire, while Salt Ash Public School has been forced to close for the day.

The Bureau of Meteorology has revised its forecast, with winds gusts of up to 90km/h now expected.

Rural Fire crews battle an out of control fire near houses along Lemon Tree Passage Road, in Salt Ash, NSW. Photo: AAP Image

As a result, the NSW Rural Fire Service has declared a total fire ban in the Hunter and increased the fire danger rating to severe.

"The fire is burning very aggressively and is moving very quickly," NSW RFS Commissioner Shane Fitzsimmons told ABC TV on Friday.

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"At the moment you're talking about dozens of properties being directly impacted as the fire moves in around the Salt Ash area."

Residents are being told to stay put, with several roads in and out of the area closed. Access to Lemon Tree Passage and Nelson Bay is restricted with people in those communities isolated.

Rural Fire crews battle an out of control fire near houses along Lemon Tree Passage Road, in Salt Ash. Photo: AAP Image/Darren Pateman

"There's a lot of concentrated effort going to stop the fire reaching the more established community areas along the (Nelson Bay) peninsula," he said.

Four large air tankers are helping to battle the blaze - including 'Gaia', the 737 which was used on Thursday in a world-first. But Mr Fitzsimmons warned stronger winds could make it too dangerous to fly any aircraft.

"It's going to be a difficult afternoon," he said.

"People need to stay well informed and be ready to act accordingly."

More than 200 firefighters are battling the blaze, which has already burnt through more than 1300 hectares.