Hundreds of homes are flooded or have been evacuated and thousands of people are without power as a complex, wild storm lashes Australia's east coast.
Gale-force winds and heavy rain downed trees, damaged properties and flooded roads from southern NSW to the mid-north coast, including Sydney on Tuesday evening.
About 200 properties in Burrill Lake on the south coast were flooded overnight, while more than 200mm of rain smashed several towns, including Morton and Ulladulla.
More than 2300 calls were received by the SES in 24 hours to 9.30am.
"It was indeed a very wild night for many people across the east coast of NSW," SES Deputy Commissioner Debbie Platz said.
"We are very grateful the communities in these areas heeded our warnings, that has meant that there has not been as much damage to property and impact to lives as what could have been, but we did see conditions deteriorate overnight."
Emergency crews had a busy workload overnight, pulling off seven flood rescues on the NSW south coast, all caused by people driving into floodwaters.
A 55-year-old man was taken to hospital with serious head and torso injuries after a tree fell and crushed his truck in Moss Vale, in the southern highlands.
Police, paramedics and emergency crews extracted the unconscious man from the driver's cabin of his truck at 10.30pm on Tuesday.
Communities stretching from Queensland's Lockyer Valley to Bega on NSW's south coast are still being warned to take care as severe weather driven by a "vigorous" coastal low lingers offshore.
The storm, called a cyclone bomb, was expected to track south on Wednesday before turning back out into the Tasman Sea on Thursday.
Isolated totals up to 120mm remain possible but conditions are expected to ease later in the day.There are 34 warnings current, with 335 properties subject to evacuation or shelter now warnings on the Central Coast and south coast.
More than 37,000 homes and business were without power and many flights have been cancelled from Sydney Airport for the second consecutive day.
Residents were being warned to evacuate amid coastal erosion on the Central Coast. Dunleith Tourist Park manager Ryan Lloyd told AAP the beaches were heavily affected as wind gusts and swells intensified.
"It's pretty wild - pretty full on - a bit scary for the home-owners too," he said.
There were patches of blue in the sky but they were otherwise surrounded by dark clouds.
But the rain was less of a concern than the strong winds.
"We've already had plenty of tree branches down ... they're dropping limbs everywhere," Mr Lloyd said.
"It's just battening down now, just wait for it to blow over - pardon the pun - then a massive clean-up for the next couple of days."
Sydney's Warragamba Dam is expected to spill in the coming days, however has not yet reached capacity after 56mm of rain in 24 hours.
The Bureau of Meteorology is predicting another low-pressure system to enter the storm's path later on Wednesday.
"We see another low-pressure system, really dumb-belling around that first one, that will really intensify and reinforce some of those winds and rain across the south coast," senior meteorologist Jonathan How said.
The system extends about five kilometres into the sky, with two low-pressure systems interacting with one another in a phenomenon known to meteorologists as the Fujiwhara effect.