3 Dead as Cyclone-Like Storm Lashes Sydney Region

Sea swells also hampered shipping as the region around Australia's biggest city suffered its second day of gale-force winds of up to 135 kilometres per hour (83 mph) and torrential rain.

The Bureau of Meteorology said 119 millimetres (five inches) of rain had fallen in Sydney in 24 hours -- the city's wettest period since 2002.

The powerful winds blanketed parks, pavements and roads with sand from beaches, including Bondi.

Dozens of flights were delayed and one cruise ship found itself stuck at sea outside Sydney Harbour.

The State Emergency Services said it had dealt with more than 3,000 calls for help and carried out 20 flood rescues.

"There have been multiple persons trapped in vehicles, being trapped in buildings and being trapped on top of buildings while trying to take refuge from floodwaters," the agency's deputy chief Steven Pearce told reporters.

Speaking earlier to the Australian Broadcasting Corporation, he said: "We've haven't seen this sort of weather pattern, this east-coast low or one as severe as this, in years."

The Sydney Harbour pilot could not board the giant Carnival Spirit cruise ship due to massive swells, with the vessel languishing in the open ocean with hundreds of passengers on board.

The Port Authority of New South Wales state said the harbour had been closed for commercial shipping, possibly for 48 hours. Ferries across Sydney were cancelled or had limited services.

New South Wales police said three people had died in the country town of Dungog, 215 kilometres (133 miles) north of Sydney.

"During the morning a woman and two men were located deceased within the Dungog township. The circumstances surrounding their deaths are still to be determined," they said in a statement.

Video footage posted online showed a wooden house being swept away by surging waters, although it was not clear if this was linked to the deaths.

ABC reported that one person was also missing near Newcastle, 150 kilometres north of Sydney, after floodwaters rushed through a campground, washing away campervans and caravans.

More than 100 schools were closed, while the electricity utility Ausgrid said more than 215,000 homes and businesses were without power across Sydney and the Central Coast area to the north.

Numerous roads were also closed due to flooding, fallen trees and downed power lines.