A DELUGE across Newcastle and the Hunter has caused widespread flash flooding, road closures, a sinkhole to open up in Wallsend and almost 300 calls for assistance to the State Emergency Service.
The rain is part of a "southerly buster" pushing its way up the coast at a slow pace, the Bureau of Meteorology's Jonathan How said.
"It crossed Sydney about midnight and headed north," the senior meteorologist said.
"We have seen flash flooding, heavy falls and a severe storm warning which has since been cancelled, but could be reinstated. The system has stretched from Redhead Beach through to Maitland."
The large amount of rain caused a sinkhole to open up in the yard of a home in Wallsend.
About 3.10pm on Wednesday Wallsend Fire and Rescue were called to Kenrick Street where a large sinkhole was still actively collapsing.
Crews advised City of Newcastle, Hunter Water and Subsidence Advisory NSW which arrived shortly after to render the area safe. Fire and Rescue conducted a site handover to the Subsidence Advisory.
"With Wallsend being an old colliery in the 1860s, this is a common occurrence after a heavy downpour. If you locate a sinkhole, avoid the area and contact Triple-0." a statement from NSW Fire and Rescue said.
Some of the biggest rainfall totals were recorded in Windale, which received 186 millimetres from midnight to 2pm and Cessnock which surpassed 103 millimetres in the same timeframe.
Many areas through the south of the Hunter saw 50 to 100 millimetres fall before 9am.
The rain has caused havoc across the region with street closures due to water on the road and the cancellation of events including the Pro-am for the TPS Hunter Valley at Cypress Lakes on Wednesday.
A spokesman for the SES said the Central Coast, Port Stephens and Hunter crews had received 296 calls for help since 8pm Tuesday, including three flood water rescues.
The hardest hit areas were Maitland, Lake Macquarie, Cessnock and Newcastle with many people reporting leaking roofs and water in houses.
Motorists continue to ignore warnings about driving through flood waters with SES crews rescuing two vehicles in East Maitland and Lisarow, as well as a horse stuck in floodwaters at Heatherbrae.
"The message is clear," the spokesman said.
"Don't drive through or enter floodwaters."
This sentiment was reiterated by Newcastle-Hunter highway patrol Inspector Mick Buko on Wednesday.
"Just don't cross water, if there is any doubt just don't do it," he said.
He warned motorists to be aware of falling trees and branches, with hot conditions followed by heavy rainfall making root systems structurally unsound.
He did however praise the majority of motorists who were doing the right thing and travelling slowly and safely around localised flooding in the city centre.
The rain is expected to head north on Thursday, with light showers and hotter temperatures expected into the weekend.
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