THE Hunter's coastline was pelted with more than 100mm of rain in less than 24 hours as the eastern part of the state was drenched between Sydney and the Mid North Coast at the weekend and into Monday.
Having been called to almost 150 jobs in the 24 hours to Monday morning - mostly between Tea Gardens and the Central Coast - including six rescues, the State Emergency Service (SES) has urged caution, with more heavy rain expected this week.
The NSW Bureau of Meteorology (BOM) recorded 107.4mm at its Nobbys weather station between 9am on Sunday and 9am on Monday.
About 18mm of that rain fell between 8pm and 8.30pm on Sunday night while just over 19mm was recorded in a 30 minute period in the early hours of Monday.
Just over 51mm of rain fell at Cooranbong, Lake Macquarie, during the same 22-hour period, while 50.2mm was recorded at Williamtown.
The SES had been called to six rescues since Sunday morning - one at Tea Gardens, three at Gosford and two at Ourimbah - which came after people drove into deep floodwater.
No-one was injured but SES Northern Zone Deputy Commander Stephen Leahy told the Newcastle Herald there were multiple people in the vehicles in many of those cases.
"So the driver and passengers are being put at risk," he said.
"It's absolutely imperative people don't take risks. If the road is flooded or indeed if there is water over the road, do not drive through it."
Mr Leahy said the SES had been called to 146 jobs in 24 hours, but the "vast majority" were in locations between Tea Gardens and the Central Coast.
Most of these were for reports of leaking ceilings and requests for sandbags, with the Port Stephens unit tackling at least 20 of these jobs including trees down, ankle-deep water in houses, roof repairs and sandbagging.
"All the teams have been busy over the weekend protecting homes by setting up sand bags, with many hands making light work," acting unit commander James Worrall said.
"Recently we have seen an increase in members of the public becoming more resilient by collecting sand bags from collection points and staying on top of household maintenance, which is a fantastic thing to see. It allows the teams to better help those in need or people with major damage to their home."
Pictures were circulating on social media of vehicles under water at Tea Gardens.
Mr Leahy said the creek hamlet north of Port Stephens easily overflowed and caused flash-flooding, but water tended to recede quickly.
"The ground is absolutely saturated," he said.
"That means that water will pool on the surface and start running down into gutters and streams ... and the likelihood of flash-flooding is much higher."
Lake Macquarie City Council warned Owens Road at Martinsville was closed and Kalaroo Road at Redhead was opening and closing intermittently on Monday due to flooding.
Several roads across the Maitland, Singleton and Cessnock areas were closed throughout the day. Drivers were urged to be cautious at Sandgate and Tomago near Newcastle due to water on the roads.
Limited buses replaced trains between Maitland and Newcastle Interchange throughout the day on Monday due to flooding on the tracks at Sandgate.
The SES advised residents on the Central Coast at Tuggerah Lake to prepare to isolate as moderate flooding was expected on Monday night and Tuesday morning.
Warnings were issued for Yarramalong, Dooralong, Long Jetty, Chittaway Point, Chittaway Bay, Tacoma South, Killarney Vale and Berkeley Vale.
It comes after significant rainfall in the lake's catchment area in the past few days.
The University of Newcastle's Ourimbah campus was closed due to heavy rain on the weekend but was expected to reopen on Tuesday.
A marine wind warning was also issued for the coast between Sydney and Byron Bay.
The wet weather on Monday saw 2.4mm of rain fall at the BOM's Nobbys weather station between 9am and 5pm.
The BOM has forecast showers for Newcastle on Tuesday, Wednesday and Thursday; and heavier rain on Friday and Saturday.