Update 8.30pm: Train link has been cut between Morisset any Wyong due to bush fires. Buses have replaced trains until further notice.

The state's fire crisis hit the northern Central Coast suburb of Charmhaven on Tuesday when a fire roared through bushland along the edge of Wallarah Creek.

The fire, which began about midday amid temperatures of more than 35 degrees, burned quickly and close to residential areas.

Multiple crews from across the coast and water-bombing aircraft responded to the blaze, which was upgraded to an emergency status level about 4pm as properties came under threat.

Flames whipped above the treeline and a large plume of smoke could be seen for kilometres in any direction.

Two large air tankers arrived to the coast about 5.30pm and attempted to douse the flames.

They were called in due to fears the fire would spread towards the M1 Motorway and main north railway line.

The fire was less than a kilometre from the rail line but train services had not been impacted at that time.

The fire had burned through more than 120 hectares by 6pm, mainly on the western side of the Pacific Highway, and was still listed as an emergency level blaze in the early evening.

However, no properties are understood to have been lost.

When the fire first took hold, freelance photographer Geoff White raced from his home at nearby Woongarrah and captured some of the dramatic scenes.

"I just grabbed my camera and bolted," Mr White said.

"I got there before police - all the roads were still open.

"It was frigging hot and enough of a breeze to fan this thing into the tops of the trees. It was crowning right through the Casuarinas and the Gums.

"It was right in among the back of the houses on the northern side of the river and ... a bunch of crews were protecting homes ... then it jumped the river and burned straight out to the lake."

Mr White said he was struck by the amount of dry vegetation in the area.

"Walking from the car down to the river, which was 100 metres from where I parked, you were walking through dry gum leaves a foot deep," he said.

"The amount of fuel that's in that area is insane."

Newcastle Herald photographer Marina Neil captured a wallaby making an escape from the fire by swimming across Wallarah Creek.

Two fishermen watched on in disbelief as it crossed the creek and hopped away unharmed.

The fire forced authorities to close the Pacific Highway in both directions between Bluehaven and Lakehaven for most of the afternoon.

A severe fire-danger rating and total fire ban had been in place for both the Central Coast and Hunter regions on Tuesday.

Another fire took hold at Liddell in the Upper Hunter in the mid-afternoon on land near Ravensworth mine.

The grass fire spread to about four hectares in size before fire crews managed to get it under control.

The New England Highway remained opened during the fire but traffic was heavy throughout the afternoon.

A very high fire-danger rating was forecast for the Hunter and Central Coast regions on Wednesday.