Australian authorities on Tuesday warned residents of the country's eastern coast that "catastrophic" floods persist in many areas after days of torrential rain.
Military helicopters, jet skis and rubber boats were deployed to rescue people stranded by dangerous flooding.
At least 15,000 people were waiting on high alert on Tuesday for potential orders to evacuate. New South Wales (NSW), the country's most populous state, has already evacuated some 18,000 people.
"It is catastrophic in its dimensions and the impact will be severe, and the fact that 15,000 people may need to be evacuated within the next 24 to 48 hours is a huge concern," said NSW Premier Gladys Berejiklian, adding that the wild weather was "impacting a huge area of the state."
Thousands of homes along Australia's populous east coast have been left damaged by the flooding.
Australia deploys defense personnel
Prime Minister Scott Morrison said the weather emergency was expected to ease by late Wednesday, but that "floodwaters remain persistent for some time."
"I'm advised that the rain and flood situation does remain dynamic and extremely complex," Morrison said, adding that the NSW government had already requested 1,000 defense personnel to help clean up after the floods.
Some parts of NSW had recorded two-thirds of their annual rainfall in less than a week. The highest rainfall total recorded was 1,083 millimeters at Mount Seaview, west of Port Macquarie on the NSW coast.
Australia's Bureau of Meteorology (BoM) issued flood warnings from the northern border with the state of Queensland "all the way down the east coast to Victoria," adding that there was a "developing flood situation in inland NSW."
The BoM said there was also a high risk of dangers associated with damaging winds, hazardous surf conditions and coastal erosion.
Worst flooding in decades
The flooding seen in NSW in recent days is the worst in decades with communities on the Mid-North Coast area north of Sydney facing the worst flooding since 1929.
Newcastle, around 140 kilometers (87 miles) north of Sydney, and the Nepean Valley west of the city are experiencing the worst flooding in some 50 years.
Government meteorologist Agata Imielska warned that even though western Sydney and the Mid North Coast will have "blue sky and sunshine returning," by late Tuesday, "flooding will continue and the flood risk will continue."