Heavy rain, damaging winds, and abnormally high tides are in the forecast.
The New South Wales State Emergency Service reported six flood rescues overnight near Grafton, north of Sydney, amid dozens of calls for help over the past two days. The people who were rescued became stranded while attempting to drive through floodwater.
Assistant Commissioner Karen Webb told Australia's 7 News that NSW Police were hard-pressed to respond to the emergency Sunday.
“There are currently hundreds of calls for assistance, including trees, boulders or power poles down onto cars and homes, and across roads, as well as power outages and localized flooding impacting various roads and traffic lights," Webb told 7 News.
Some east coast towns have received in recent days their heaviest rainfall in five decades as Australia's Bureau of Meteorology warned of "dangerous conditions" this weekend.
The heavy rains have also caused roadways and railways to be flooded. High winds in Sydney caused a tree to fall on a car in the city center Sunday afternoon, injuring four people.
But the NSW Rural Fire Service said the recent rains put out the Currowan Fire south of Sydney late Saturday after it destroyed 312 homes and blackened 1.2 million acres over 74 days.
Rural Fire Service Commissioner Shane Fitzsimmons said he hoped the heavy rain would move inland from the coast and drench more of the major fires that have been raging for months.
Fitzsimmons bid farewell at a Sydney airport hotel on Sunday to 21 American and 21 Canadian firefighters who were heading home after their deployment battling the blazes.
The wildfires have killed at least 33 people and destroyed more than 3,000 homes in an unprecedented fire season that began late in a record-dry 2019.
The Associated Press contributed to this report.