RNZI reports the Bureau of Meteorology (BoM) cancelled a severe weather warning for New South Wales, but flood warnings remained in place for many rivers around the state.
The wild weather prompted evacuation notices for Northern Lismore, Chipping Norton, Billinudgel, Ocean Shores, Golden Beach, New Brighton and Coffs Creek last night.
State officials said emergency services had received more than 8000 calls for help and carried out more than 250 flood rescues over 48 hours.
Power was slowly being restored to 30,000 NSW homes blacked out by the severe weather.
A flood evacuation warning was issued for people living along the Georges River in Sydney's south-west.
Emergency services are also working frantically to save a number of homes at Collaroy in Sydney's north, where four sink holes had developed.
Police were going door to door in the Northern Beaches, where huge surf was also causing widespread coastal erosion.
More to come
The weather system has extended down to Tasmania, with an "exceptional" swell up to 8m expected to hit Tasmania's north-east today.
The state is predicted to receive up to 200mm of rain in the coming days, with warnings of flash flooding.
Two evacuation centres were opened overnight to assist residents affected by flooding along the Mersey River, at Wynard Railway Institute Hall and East Davenport Recreation Ground.
Heavy rain and flash flooding was also expected to hit East Gippsland, Victoria.
The MetService website said a complex trough was expected to approach New Zealand on Wednesday, with a moderate likelihood of heavy rain around Westland, Fiordland, the Otago and Canterbury headwaters and Buller over the following three days.
A ferry terminal was submerged by the overflowing Parramatta river in Sydney yesterday. Photo: AFP