Crews remain cautious about a southerly wind change expected to come through in the evening.

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The fire at Greta remains at emergency level and has burned through at least six hectares of bushland.

Residents are advised to seek shelter and follow instructions from fire crews on the ground.

About 30 trucks plus aircraft are on scene. Another 25 trucks remain on scene at North Rothbury, where a fire remains at Watch and Act level.

Lower Hunter RFS public liaison officer Terry Burns said two firefighters have been taken to Maitland Hospital in a stable condition. One fell and suffered a head injury and the other experienced smoke inhalation.

Cessnock City Council has established an evacuation centre at Greta Workers Sports and Recreation Club, and urges anyone at Miller Park to relocate there.

Mr Burns said crews were still battling bad winds on the fire ground and were preparing for a southerly change to come through, which could swing the fire around.

A fire at Greta is at emergency level while the blaze at Wine Country, Drive has been downgraded to Watch and Act.

An evacuation point has been established at Greta Workers club, 2 West street, Greta. Another has been set up at Cessnock Showground, 111 Mount View Road, Cessnock for animals only at this stage.

At least three properties were damaged in the North Rothbury blaze. An RFS spokesperson said North Rothbury residents are advised to follow the directions of fire crews on the ground.

Twenty-eight trucks, including 10 from Victoria, are on scene at a fire at North Rothbury.

Lower Hunter RFS public liaison officer Terry Burns said the fire was believed to be roughly three to four hectares in size and broke out just west of the North Rothbury township.

Three helicopters and one aircraft have also been deployed.

Mr Burns said there had been unconfirmed reports of damage to structures in the area.

The fire remains at emergency level. Residents should shelter in place. It is too late to leave.

An emergency warning has been issued for a fire at Wine Country Drive at North Rothbury.

The NSW Rural Fire Service said on its Facebook page that the fire was burning in the area of Wine Country Drive at North Rothbury and spreading quickly.

"Property is under threat," the RFS post said.

"If you are in the area of North Rothbury, it is too late to leave. Seek shelter as the fire approaches."

Lower Hunter RFS public liaison officer Terry Burns said 15 trucks were on scene at 3.15pm and 10 more were inbound. Three helicopters have also been called to the incident.

Mr Burns said there had been an unconfirmed report of a structure fire in the area.

All roads in and out of North Rothbury are currently closed.

More to come.

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