Wave of SES calls as thunderstorms hit NSW

SES crews have been responding to calls about fallen trees and damaged roofs after a storm hit NSW. (Murray McCloskey/AAP PHOTOS) (AAP)

Emergency rescuers in NSW have been swamped with close to 300 calls for help within the space of a few hours, as dangerous wind gusts and heavy thunderstorms hit NSW.

Severe cells and dangerous winds battered Sydney and inland parts of NSW on Monday before tracking towards the state's north, Dean Narramore from the Bureau of Meteorology said.