An enormous clean-up has begun in Sydney’s south, following the fierce storms yesterday which produced a tornado and wind gusts up to 213km/h.

Around 500 calls for assistance were made to the State Emergency Service (SES) as roofs were ripped off and trucks overturned, with the suburb of Kurnell the worst hit.

A natural disaster zone has been declared in the area and aerial images from the 9NEWS chopper this morning showed the full toll of the storm.

(9NEWS)

(9NEWS)

SES Deputy Commissioner Greg Newtown said crews were preparing to examine the damage today and assist with the clean-up.

"We had over 50 crews in the field yesterday, we’ll have more crews out there today," Dep. Com. Newtown said.

"The main issue today is going in there assessing what damage still remains to be addressed, and of particular interest today is around the asbestos hazard."

(9NEWS)

Yesterday, Superintendent Michael O'Toole said people should wear a protective mask and clothing before entering their property if it was damaged in the storm.

He said homes built before 1987 were the most likely to contain asbestos.

"People should take general safety precautions. We have been advised the risk is low if debris is not disturbed," he said.

During the savage storm, Kurnell Public School and a nearby desalination plant were evacuated, and further north near the city, three floors of Westfield Bondi Junction shopping centre were evacuated following a partial roof collapse.

Some residents returning to Kurnell yesterday were disgruntled by roadblocks preventing them accessing their homes.

Police said some locals "disobeyed" orders to move on from a roadblock on Captain Cook Drive, however eventually residents were allowed to begin cleaning up their damaged homes.

IN PICTURES: Fierce storm batters NSW

A bird's eye view of the trail of destruction weaved through Kurnell by the tornado. (NSW Fire and Rescue)

Powerlines brought down in Kurnell. (Twitter)

Last night, the state government said Kurnell residents and businesses affected by the storms would be able to dump rubbish at tips without being charged.

"The NSW government will help by waiving the waste levy for all waste in the Kurnell area, including bulk waste and asbestos generated from the storm," Environment Minister Mark Speakman said.

Yesterday, a tornado wreaked a path of destruction through Kurnell, leaving rows of flattened trees, downed powerlines and damaged houses.

Powerlines and trees were brought down and homes and business sustained extensive damage after the tornado rolled in from the coastline.

Golf ball sized hail stones, flash flooding, heavy rain and wild winds battered the region, while the NSW Central Coast and much of Sydney also received a savage downpour.

Do you have photos or video of the storm? Send them to contact@9news.com.au but please stay safe.

Homes were damaged, powerlines downed and trees knocked over as the storm hit Kurnell. (Westpac rescue helicopter)

The trail of destruction after damaging winds hammered Kurnell. (Westpac rescue helicopter)

Fortunately, today the weather is expected to ease, with Sydney forecast to be partly cloudy with a 50 percent chance of rain.

Meteorologists yesterday said while tornadoes were not unusual, the vortex that struck Sydney was particularly fierce.

"When you look at the wind speed and amount of rain recorded, it lends itself to a tornado in the area," the Bureau of Meteorologist’s meteorologist James Taylor said.

"Looking at the radar, it was just so intense – it’s highly likely that we’ve broken a wind gust record in NSW."

The storm as it approached Sydney. (Bureau of Meteorology)

The Bureau of Meteorology said yesterday’s storm was similar to the devastating April 14, 1999 hail storm that caused extensive damage in that it had gathered offshore rather than in Sydney’s west or over the inland regions.

"This is a pretty unusual event – we’re used to these storms forming in the afternoon… coming in from Western Sydney or the ranges, it’s unusual to have such an event before lunch," meteorologist James Taylor said.

"We’re seeing lots of moisture and a high pressure system that was sitting in the Tasman Sea that worked its way across the coast overnight, allowing it to become so intense.

"To get so many things like this together is very unusual."

Large hail was reported across Sydney's south. (Instagram/Rebecca Murphy)

(Twitter/@EduRidden)