Pacific Highway fire still afoot and fuelled by Hunter heatwave warning

Two fires burning at Port Stephens on Saturday along the Pacific Highway and Karuah combined over night to create one fire front on Sunday which kept more than 70 firefighters busy.

NSW Rural Fire Service Chief Inspector Ben Shepherd said that by 3pm Sunday the Karuah Pacific Highway fire had consumed 777 hectares.

While none of the 20 nearby homes were considered under threat, northerly winds were expected to increase during the course of the day and shift easterly around mid-afternoon which may force some road lane closures.

"There's no doubt that we are seeing a high fire danger throughout the Hunter including the area towards where this fire ground is," Inspector Shepherd said.

"The good news is at the moment winds are not extremely strong so we are not looking at extreme fire danger."

Winds were started to shift more to the east as forecast but other than a few flare ups and an increase of activity, fire fighters, assisted by water bombing, were holding the line, he said.

"Fire fighters will look at back burning tonight and trying to hold those identified containment lines east of Bucketts Way which they're having some success in doing," Inspector Shepherd said.

A much smaller fire burning at Cessnock on Murrells Road, Olney, had been brought under control by early Sunday afternoon.

A third fire which started at Fisherman's Bay Road, Anna Bay, on January 29 remains contained with monitoring of internal hotspots continuing.

The Bureau of Meteorology (BOM) has issued a severe heatwave warning for large swathes of the Hunter region.

Daytime temperatures of between 35 and 41 degrees are forecast for the rest of Sunday and Monday with the chance of a thunderstorm.

Newcastle was expected to reach a high of 31 on Sunday and 32 on Tuesday, with temps of 37 expected in suburbs like Waratah, and up to 41 degrees in Singleton.

A few millimetres of rain may be on the cards for parts of the region come Tuesday afternoon and cooler temps.