There are grave fears for the safety of two people whose car was swept away by rising floodwaters in New South Wales this morning.
Wild weather has wrought havoc on the Hunter Valley, Sydney, Central Coast and Illawarra regions over the past two days.
A search is underway for two people, who are believed to be in a car that disappeared near Maitland in the Hunter Valley, as the deluge hitting New South Wales continues.
Police divers are in the water and a rescue helicopter is searching from the air.
Four people who tried to rescue an elderly woman and another person in the car at Cessnock Road, had to be rescued themselves after getting into difficulties.
The police inspector at the scene Greg Rankin said it was feared the car's occupants were now dead.
"Looks like it was two people dived into the water to assist the people that were in the car that had gone submerged. Those two persons needed then rescuing, and fire and rescue crew rescued them and brought them to shore but unfortunately it looks like submerged car went under and unconfirmed reports that there possibly is two persons deceased in that vehicle."
'Largest storm operation in the last 10 years'
New South Wales authorities say they are dealing with the largest storm operation in a decade after three people were killed in "cyclonic" conditions.
The Bureau of Meteorology said winds were expected to reach gale-force on the coast today and rain could be heavier than yesterday before conditions ease later in the day.
Some 200,000 homes are still without power and almost 100 people have been rescued from floodwaters.
Emergency services have responded to more than 8000 calls for help to address flash flooding, fallen trees and downed powerlines.
On Tuesday morning, three elderly residents were found dead in the town of Dungog, north of Newcastle, where more than 300 millimetres of rain fell in less than 24 hours.
Authorities said the circumstances around the deaths were still being investigated.
Locals said several homes were washed away, and a woman and two children were rescued from a house as it was washed down a street in nearby Greta.
Sydney Harbour has been closed to commercial shipping, leaving a cruise ship with some 2500 passengers waiting off the coast, battered by big swells.
State Emergency Service (SES) deputy commissioner Steve Pearce said the storm was like nothing he had seen before.
"I haven't seen a storm of this magnitude in my time here at the SES and, indeed, this would be the largest storm operation in the last 10 years," he said.
"We've never seen these cyclonic winds last for 24 hours straight. That's what's caused the majority of the damage.
"We've had over 6500 requests for assistance and on top of that, with the enormous amount of rainfall - up to 320 millimetres in over 24 hours - we've seen about 80 flood rescues. We've seen homes washed away, whole streets decimated."
He said thousands of emergency services were on the ground and more were coming in from around the state to help on Wednesday.
NSW Premier Mike Baird has urged commuters to travel outside of peak times and called on employers to be flexible with work arrangements.
Dungog local police commander Jeff Loy said the deaths of three elderly people in the area - two men and one woman - occurred in different locations and circumstances.
"I understand there has been footage also of a house going down the river. These people are not related to any of those houses that have been taken off their piers."
Dungog resident Tracy Clifton said her friend barely made it out of his house alive.
"I was speaking to one of the fellows who live there and he said he saw the water coming up across the road and decided to get out," Ms Clifton said.
"He got out the family and the kids and he said when he went back in the water was already up to his waist so he thought he'd better get out as well.
"And it was only a matter of minutes and his house was gone, was taken down the stream."
Dungog Shire Council Deputy Mayor Tony McKenzie said the town was "very, very quiet and sombre".
The town of Greta was also hit hard. One resident, Henry, had to be rescued as his house was swallowed up by water.
"It was a bit scary, especially when I walked outside," he said.
"By this time it just rose so quickly. I was rescued by some neighbours and the water was chest high."
Damaging weather continues
The Bureau of Meteorology has maintained its severe weather warning for damaging winds and surf and heavy rain along the coast from Illawarra to the Hunter.
The service said an intense low pressure system was centred just off the Hunter coast, near Newcastle.
"This low is expected to remain slow-moving, maintaining vigorous winds, large seas, and periods of heavy rain and thunderstorms," it said in an update just after 4am AEST.
"Conditions are expected to slowly ease during Wednesday as the low weakens."
The storm has left local authorities across the region facing a huge clean-up task ahead of Anzac Day, with Newcastle Lord Mayor Nuatali Nelmes telling ABC's AM the bill could exceed the $AU1.7 billion spent in the aftermath of 2007's Pasha Bulker disaster.
The Insurance Council of Australia said it had received more than 19,500 claims so far and had declared a catastrophe in storm-hit areas.
- ABC / Reuters