The Bureau of Meteorology is warning of potential flash flooding in the Hunter as heavy rains from ex-tropical cyclone Oswald continue to hammer the region.
The low-pressure system is moving south from Queensland, bringing with it fears of flooding with about 200 or more millimetres of rain expected today.
The Williams and Paterson Rivers are under flood watch, while damaging winds and surf conditions are predicted.
The bureau's Julie Evans is urging people to listen to warnings and stay out of low lying areas.
"Yeah, really urge people to listen out for the warnings and keep out of low lying areas, I guess is probably important as well and only travel if necessary," she said.
"There is a potential for, as I say, flash flooding and very strong winds and so the safest place I guess would be indoors."
Ms Evans says people might look at changing their travel plans.
"People should really be looking closely at the necessity to be travelling," she said.
"Certainly the SES message is people who do have to travel to just drive to the conditions and please do not drive through flooded waterways."
After being kept busy with several calls yesterday, the State Emergency Service is gearing up for another big day in the Hunter as the worst of the wet weather passes through.
Residents and holiday-makers are being urged to take care and tie down any loose material that might blow away with today's predicted strong winds and gusts of up to 100 kilometres an hour.
SES Hunter deputy regional controller, Ken Speer, says it is likely to be a rough day.
"We'll certainly have all our, you know a number of our volunteers around the region are out and answering to the jobs as they come in and they are continuing to monitor that situation," he said.
The SES is urging motorists in the Hunter region to resist the temptation to cross flood waters
Mr Speer says people could run into trouble if they tempt fate with flood waters.
"The potential with the flash flooding is that people tend to either drive or walk through that water because they have to get, they feel they have to get somewhere," he said.
"We would certainly say that they should never drive or walk through the flood waters - you don't know what's in them and maybe below it the possibility is that the ground could have broken away below that water and you could be driving into a hole."
© ABC 2013
12:19 EST A hail storm barged through Sydney yesterday afternoon, bringing 1-2 cm sized pellets and heavy downpours.