Three people were killed in floodwaters from a strong storm that pounded Australia's east coast over the weekend, with drenching rains and huge ocean swells forcing some coastal residents to flee their homes and sending a swimming pool sliding into the sea.

The body of a 65-year-old man was found in a car today in a creek near the town of Bowral, about 120km south of Sydney, while the body of another man was found in a truck washed away by floodwaters in the southwest Sydney suburb of Leppington, New South Wales, state police said.

In the nation's capital, Canberra, a 37-year-old man died after powerful floodwaters flipped his truck over and swept it away.

The storm whipped up waves as high as 12 metres which caused severe beach erosion and forced hundreds of coastal residents to evacuate. .


Power was knocked out to more than 85,000 homes and businesses over the weekend. Nearly 300 people needed to be rescued from flooded areas across New South Wales, the state emergency services agency said. Many of those people had attempted to drive or walk across flooded roads.

There will be little reprieve for the homes teetering on the brink of the ocean on Sydney's northern beaches with another king tide as high as the last predicted tonight.

Meteorologist Phil Perkins said the weather bureau was expecting the next king tide to peak about 9pm (AEST) tonight "with a main window of threat" between 6pm and midnight.

It will follow "the biggest king tide of the year" which joined forces with the east coast low-pressure system and created huge seas which swept away the yards of multi-million-dollar beachfront homes on Collaroy and Narrabeen beaches.

The Massive storm and huge swells have knocked parts of these houses and a pool halfway into the ocean at Coloroy beach on Sydneys northern beaches. Photo / Daily Mail Australia
The Massive storm and huge swells have knocked parts of these houses and a pool halfway into the ocean at Coloroy beach on Sydneys northern beaches. Photo / Daily Mail Australia

Mr Perkins said tonight's king tide would be "fairly similar".

"Our normal highest astronomical tide is an increase in sea levels around 1.2m and last night we saw 1.3m and this evening will be fairly similar, around 1.3m above normal sea," Mr Perkins said.

The ocean will come as close to the houses as it did last night but the waves on top of the king tide will not reach as high, according to the Bureau of Meteorology.

The high tides, fanned by the weekend's monster storm, eroded huge swathes of Narrabeen and Collaroy beaches.

Up to 10-15m of waterfront land washed away at Collaroy overnight as residents returned to their homes to assess the damage after being evacuated on Sunday night.

In total, seven homes and a unit block in Collaroy were evacuated as 8m waves slammed the coast leading to major erosion, police said.

A devastated Zaza Silk, from Collaroy, described her "worst nightmare" as she watched her pool and garden slip into the ocean after the savage storm.

"Within three hours we had a garden that was just totally destroyed - gone," she told Channel Seven's Sunrise programme as she looked at her home from police tape as the sun rose this morning.

She described how the water got "closer and closer" until police told residents to evacuate.

Resident Zara Silk nearly collapses when she sees her home. Photo / News Corp Australia
Resident Zara Silk nearly collapses when she sees her home. Photo / News Corp Australia

"I never thought it would be this bad," she said.

She revealed on Channel Ten's The Project earlier tonight that she also lost something very personal to the storm.

"My mother was in an urn in the garden along with my beautiful dog who passed away recently," she said.

"I would go and talk to them regularly and they're gone."

She said her local council has "known about this for a long time and should've put a wall up" earlier.

"They've had this happen before. This could have been avoided."

Collaroy homeowner Tony Cagorski said he and his family evacuated Sunday about 6pm and returned home this morning to survey the damage.

"It's very scary, I hope we can save the house," he told Channel Seven. "We were told to evacuate at about six, and I came back this morning and ... Wow ... It's shocking."

Mr Cagorski's home has suffered serious structural damage and the balcony has been left precariously teetering on the edge of the shoreline where his front yard once was.

"Now I know what Fiji went through and Vanuatu, it's similar to that," he said when asked to describe the storm.

Local resident Craig Graham has lived in Collaroy for nearly four decades and was among those checking out the damage Monday morning.

"It's the worst I've seen it here ... I have never seen it come up this high with this amount of storm surge and I've been living here about 40 years," he told the ABC. "It's pretty much a disaster zone."

Mr Perkins told Sydney, including the northern beaches, was expected to experience "light rain" this afternoon but said the worst of the strong winds and heavy rainfall was "behind us".

But the fallout and continued threat to homes was far from over.

A number of sinkholes have now opened up along the coastline threatening more damage to homes. Emergency crews are on site trying to save the beachfront properties.

Local resident David told the ABC: "There is no beach at Collaroy," he said.

"I wouldn't be calling it Collaroy Beach anymore, I'd be calling it Collaroy Point."

One Collaroy resident Matt Kemp posted footage of the carnage, which shows a pool washing into the ocean.

"I also saw power poles, wheelie bins and roofs and heaps of garden furniture washing past," Mr Kemp wrote on Facebook.

"Pretty crazy. No rain for ages and then whoosh, have a bit of that."

Heavy rain is predicted to continue across central and southern parts of the state as the monster east coast low that lashed Queensland and NSW over the weekend heads south towards Tasmania.

Rivers are expected to rise throughout the day in areas around Sydney, and are having a major impact on traffic and public transport in western Sydney.

The SES has had about 9000 requests for assistance, and still haven't been able to attend about 3000 of those. About 30,000 homes in the city and on the Central Coast were left without power.

A combination of the tide, the storm and the direction of the wind meant the beachside homes were the target.

- additional reporting AP