Wild weather causes more than 100 flights to be cancelled in Sydney on Friday - here's how they're looking for Saturday

More than 100 flights into and out of Sydney's domestic and international airports were cancelled due to the extreme weather on Friday. 

The storm which hit the airport at around 2pm were behind most of the flight cancellations, though some had been cancelled or diverted before that.

Domestic lights affected included those to Canberra, Armidale, Melbourne, Gold Coast, Mildura, Adelaide, Brisbane, Albury, Hobart and many other cities and towns.

International flights cancelled included those to Port Vila in Vanuatu, Beijing and Qingdao in China and Rarotonga in the Cook Islands. 

Despite a possible backlog things are looking better for Saturday, but 14 flights have already been cancelled. 

No international departures listed for Saturday have been cancelled at this stage.

Sydney Airport said passengers should check with their airline regarding the status of their flight.

The massive rainfall and high winds also caused chaos on the roads and rail networks. 

Millions of people were warned not to drive as the major weather event wrought  havoc, with the deadly deluge battering the east coast. 

All residents of NSW were told not to leave their homes unless their trips were 'necessary'.

The problem was caused by two major weather systems merging together, bringing as much as 300mm of rain from south-east Queensland to NSW's South Coast on Friday.

The rare weather phenomenon, known as a Black Nor'easter, plunged some areas into darkness in the middle of the day.