A severe thunderstorm hit parts of Sydney on Friday afternoon and damaged more than 100 properties, with the Bureau of Meteorology issuing a "severe thunderstorm warning" for flash floods and damaging winds over the next several hours.

The storm left more than 7,000 people without electricity in parts of the city, the Sydney Morning Herald reported.

Storms in Australia are not uncommon, specially during its cyclone season that runs from Nov. 1 to April 30, as storms form in the tropical waters off the northeast and northwest coasts before making landfall.

The New South Wales State Emergency Services (SES) has received 800 calls for help over the last three days, spokesman Phil Campbell said by phone.

That is far less than the 6,000 calls received in a 2007 storm and 20,000 calls in 1999, when Sydney faced its heaviest storm ever, Campbell said.

The SES is on standby for Saturday when a severe storm is likely to hit the city.

"We are looking at some very severe storms tomorrow. We are quite concerned there could be some particularly nasty storms," Campbell said, citing the meteorology department's forecasts.