The Bureau of Meteorology issued a gale wind warning for the Hunter on Tuesday, which will be accompanied by up to another 100mm of rain in some parts of the region.

Weatherwatch director Don White said the low pressure trough that was bringing moist, easterly winds to the area was expected to move out from Tuesday night.

"It is expected to clear tomorrow night and be fine the rest of the week," Mr White said on Monday. "The Hunter Valley should wake up to clear skies on Wednesday."

But before then, the region looks to be in for a sixth day straight of heavy downpours.

A severe weather warning remained in place on Monday afternoon for damaging winds, heavy rainfall, abnormally high tides and damaging surf, with those conditions expected to continue on Tuesday.

The State Emergency Service said major flooding was occurring along the Wollombi Brook at Bulga on Monday and moderate flooding was likely along the Wollombi Brook at Wollombi last night and into today. Minor flooding may occur in the Lower Hunter from this morning.

Mangrove Mountain received another 112.9mm of rain in the 24 hours to 9am Monday, Williamtown had 65.22mm in the same period, while 49mm fell at Newcastle and 48mm was recorded at Cooranbong.

The SES received 831 calls for assistance from people across the Hunter and Central Coast in the 24 hours to 4pm Monday.

Wyong was the worst hit with 266 jobs, while units in Gosford (135 calls) and Lake Macquarie (104 calls) were also kept busy.

Alysha Springett from Port Stephens SES said the unit had handed out "well over 2000" sandbags so far with stations set up at Raymond Terrace and Hinton.

While a slight rain reprieve on Monday meant some river levels in the region started to drop, Hunter SES spokesperson Mandy Bramble said that could change again quickly.

"The catchments are just so wet," Ms Bramble said. "It's only going to take a heavy downpour for them all to kick off again."

Several public schools across the Hunter were closed due to flooding on Monday. Dungog public and high schools announced yesterday afternoon they would reopen on Tuesday.

The Catholic Diocese of Maitland-Newcastle advised St Joseph's Primary Schools at Bulahdelah, Gloucester and Taree will remain closed on Tuesday, as will St Clare's at Taree.

St Joseph's Primary School, Wingham and St Joseph's Primary School, Dungog will reopen for supervision purposes only.

Mr White said the recent weather event was comparable to intense rains that affected some parts of the state in February last year, but the difference was that came directly after years of drought.

"That really broke the drought," he said. "Warragamba Dam was 40 per cent full and went to 80 per cent.

"On this occasion with a fair bit of rain over summer, the dams were already 95 per cent full so there has been more flooding."

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