Sydney wakes to storm damage headache

The Sydney region is waking to a trail of damage left by thunderstorms and powerful winds.

The State Emergency Service responded to more than 500 requests for assistance on Sunday but no injuries were reported.

Strong gusts, some in excess of 100km/h, were the main culprit as a southerly change swept up the coast after a blistering morning.

They caused a tree to crash through a living room on Sydney's north shore and damage to cars at Camden Hospital in the city's southwest.

The worst of it had blown past by 8.30pm, and the Bureau of Meteorology cancelled severe weather warnings for the Sydney region.

Earlier, swimmers ran from Sydney beaches and a music festival at Randwick was abandoned as a wall of dark-grey storm clouds swept in from the south around 4pm.

A lightning strike started a fire at a shop in The Rocks, while the Westpac rescue helicopter responded to several reports of overturned boats, jet skis and kayaks in Sydney's south.

Suburban trains were disrupted along with flights at Sydney Airport, where winds of 96km/h were recorded.

Monday will be cloudy but calm in comparison, with a forecast high of 24C.