Residents look over a flooded road near Windsor on the outskirts of Sydney, Australia. File/AP
A man swept away by floodwaters in the city's northwest was rescued by emergency crews, media reported, while television footage showed vehicles struggling to cross waterlogged streets, fallen power lines and trees, and debris floating in rivers.
Residents of a nursing home were evacuated overnight as emergency crews urged the harbour city's 5 million residents to avoid unnecessary travel and brace for possible evacuations.
"This is a highly dynamic situation. These events are moving exceptionally quickly," New South Wales emergency services Acting Commissioner Daniel Austin said during a media briefing. "Exceptionally sharp, short bursts of rain" have been creating flash flooding almost every hour, he said.
A building is surrounded by floodwaters in Londonderry on the outskirts of Sydney, Australia. File/AP
Sydney has received 1,227 mm (48 inches) of rain so far this year, more than its average annual rainfall of 1,213 mm. Over the next 24 hours, many coastal towns could get up to 180 mm (7 inches), the Bureau of Meteorology said.
The tourist hot spot of Bondi recorded around 170mm over the 24-hour period to 9am on Thursday (2300 GMT, Wednesday), official data showed.
Thousands have been ordered to evacuate their homes while businesses cleared essentials to help mitigate their losses.
"All hands are on deck to try and save some furniture ... so we have been pretty busy lifting things up... moving things away, unplugging filters and electricity, and things like that," Nicola Gilfillan, a cafe owner in southwest Sydney, told ABC television.
Overflow from a fuel pit at a site owned by oil refiner Ampol in Sydney's south caused oil to mix with flood waters but emergency crews said the spill has been contained and that there was no risk of danger in the area.
A severe weather warning stretched along the south coast of New South Wales over a distance of more than 600km (373 miles) but conditions are expected to ease from Thursday evening, the weather bureau said.
The national weather bureau warned of "a tough 48 hours ahead" for Sydney, with 60,000 people subject to evacuation orders and warnings across the affected areas, according to emergency services.
Victoria, home to Melbourne, is expected to be the worst-hit state with authorities urging residents in remote regional areas to stock essential supplies for at least three days as they fear rapidly rising waters could cut off entire towns.
Around 500,000 people in Sydney and its surrounds had by Thursday been told to evacuate or prepare to flee floodwaters as torrential rain lashed an extraordinarily long stretch of the Australian east coast.
Several towns across northern New South Wales and southeast Queensland were still battling to clear tonnes of debris after devastating floods earlier in March killed at least 21 people and swept away hundreds of farms, houses and livestock.
In a powerful demonstration of global solidarity, governments, businesses, investors and philanthropies have announced over $57 billion (Dhs200 billion) across the climate agenda in just the first four days of COP28.
Masdar City hopes to set a new industry standard for houses of worship in the region through an innovative design that blends environmental protection with cultural heritage and community building.
Coinciding with the UAE’s hosting of COP28, the CBUAE, in cooperation with the COP28 Presidency, on Sunday organised an event to facilitate global climate finance solutions and progress towards a sustainable future.