More than 60,000 homes and businesses in Sydney lost power due to a storm that swept across the city on Saturday evening, causing significant disruption.

At Barangaroo, several people suffered minor injuries after a sail was ripped from a boat at the end of the SailGP sailing event.

Several demountables were displaced or damaged in the strong winds, causing the area to be evacuated.

Event organisers said no one had been seriously injured in the incident "as far as we know", but announced Sunday's race events would be cancelled.

"A full assessment of the damage is underway but it is likely some of the future SailGP events may also need to be delayed," SailGP said in a statement.

Drivers were urged to exercise caution as traffic lights at several intersections were blacked out, and part of a major tunnel connecting Sydney's northern and western suburbs was closed for four hours due to a power failure.

Fallen trees on tracks caused some trains to stop running, interrupting services and causing whole-network delays, however services were restored by about 10.30pm Sydney time.

Sydney Airport recorded wind gusts of up to 93kph, while Molineux Point and Moss Vale recorded gusts up to 106kph.

The storm eased midway through the evening, with the Bureau of Meteorology confirming the immediate threat had passed as of 9.05pm.

However, the bureau said the situation would continue to be monitored and further warnings would be issued if necessary.

Energy providers worked to fix downed power lines as the storm eased, with Endeavour Energy saying the main areas affected were in the city's north-west.

Almost 20,000 properties across the state remained without power as of just after midnight, according to Ausgrid, which services Sydney, the Central Coast and the Hunter Valley. 

Fire and Rescue NSW said it responded to numerous incidents across the Sydney metropolitan area, with power lines and trees down as well as people stuck in lifts.