The State Emergency Service has responded to about 1200 calls for help in 24 hours - three quarters of those in the Hunter, Central Coast and Mid North Coast regions.

The SES set up an evacuation centre at Bulahdelah Golf Club (on Recovery Road), as floodwater was expected to pass 3.5m at the town's bridge on Wednesday night.

Residents in low-lying areas of River Street, Myall Street, Richmond Street (west of Alexandra Street), Stuart Street (west of Alexandra Street), Stroud Street (south of Stuart Street), Blanch Street (west of Crawford Street), Prince Street (south of Richmond Street), Jackson Street and Alexandra Street (south of Stuart Street) have been asked to evacuate.

Evacuation orders put in place in recent days for parts of Bulga, Broke, Combo, Whittingham, Scotts, Dunnolly and Glenridding remained in place on Thursday morning - as did evacuation warnings for Singleton township, Duckenfield, Millers Forest and Belmont (near the lake).

SES spokesman Ashley Sullivan said the agency received about 1200 requests for help in the past 24 hours, with about 900 coming from the Central Coast, Hunter and the Mid North Coast regions.

"We've seen about 65 flood rescues in the last 12 hours alone so our crews are still keeping very busy," he told the Seven Network on Thursday.

"We still have that flooding in the Hawkesbury Nepean valleys, so we've got a big focus on that."

More than 6000 Hunter residents have fled to higher ground as rising water levels threaten their homes, while the New England Highway remains closed at Singleton and Maitland.

The SES said major flooding was occurring at Bulga - 1m higher than the 1952 level - after it peaked on Wednesday afternoon.

Major inundation at Singleton was also taking place on Thursday morning, with the flood level expected to reach a peak of about 13.71m - exceeding the level of 13.15 reached in March.

Significant river rises have causes moderate inundation at Wollombi Brook.

Moderate flooding is occurring at Maitland and there is minor inundation at Raymond Terrace.

"Further rainfall is forecast for the next 6-12 hours however the heaviest rainfall has cleared the Hunter Catchment and is expected to continue to ease throughout Thursday," the SES said.

Several roads remain closed due to flooding - most notably Tomago Road between Graham Drive and Masonite Road, the New England Highway between Melbourne Street and Bungaree Street at Maitland, Cessnock Road between the New England Highway and Avery Lane in the infamously flood-prone Testers Hollow area, Putty Road between Milbrodale Road and Wambo Road, the New England Highway between Kelso Street and the Golden Highway and the Golden Highway (Mitchell Line of Road) between the New England Highway and Range Road.

It comes after the Herald reported the wild weather was causing "absolute bedlam" throughout the region on Wednesday.

Meanwhile, Maitland MP Jenny Aitchison said she has written to the state and federal governments seeking an immediate natural disaster declaration for Maitland.

Singleton and Maitland were left off a list of 23 local government areas declared natural disaster zones earlier this week, which unlocked joint state-federal support for affected residents and businesses.

Cessnock was included on the list.

"Given the extent of this significant weather event my community has experienced to date, and the expectation that the event will continue, with the possibility of moderate flooding, my community are begging for assistance," Ms Aitchison said.

"Already we have seen destruction of local road infrastructure, and property significantly damaged by severe weather and in particular an area of concern is the suburb of Gillieston Heights, who have been completed isolated overnight with access being cut at Testers Hollow on one side and at Cessnock Road/New England Highway on the other. I also have concerns for 100 plus residents in the Oakhampton area and over 1000 people who reside in Lorn who also could become isolated.

"Maitland residents and businesses are desperate for assistance to ensure their communities and businesses can continue to survive. We already have local farmers suffering due to previous weather events and we are now dealing with the devastation of flooding once again.

"It is essential that our community, businesses and local council get flood relief as soon as possible. I have also requested that all available resources and assistance be given to our local emergency services as they deal with the impacts of these continuing severe weather systems."

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