A man is dead, thousands of people are without power and travel plans for commuters will be disrupted after thunderstorms wreaked havoc across Sydney and coastal New South Wales just weeks after record downpours.
Damaging winds of about 110km/h hit North Head on Tuesday night, with other areas also blasted by gusts over 100km/h.
State Emergency Service assistant commissioner Paul Bailey said there were more than 900 calls for help, with north Sydney suburbs worst affected.
"We are doing our best to work with the electrical companies to get power back as quickly as we can," Mr Bailey told the Nine Network.
"But we envisage a long, long day, into tonight and obviously tomorrow we'll be continuing on - a big clean-up for everybody going forward."
A 37-year-old man died after being hit by an airborne gas bottle around midnight when he was walking in Harrington St in The Rocks.
He later died at St Vincent's Hospital.
The Bureau of Meteorology warned storms are likely to continue early on Wednesday in central NSW before moving towards the northeast.
Transport for NSW says Sydney North Shore commuters should plan their trips, with delays expected on several routes affected by a fallen tree at Pymble, and other train services also affected on the T9 line.
"Some @T1SydneyTrains and @T9SydneyTrains services are affected following last night's severe weather conditions - trains are running though journey times may be longer," it tweeted on Wednesday morning.
At Terrey Hills, the roof was ripped off the local golf club.
Endeavour Energy said electricity cuts were affecting 14,000 of its customers after power lines were brought down in northwest Sydney and the Hawkesbury region on Tuesday night, with 350 electrical hazards needing repairs.
Ausgrid said its power network had been damaged by the intense lightning storm in Sydney, with about 50,000 properties left without electricity. Almost 30,000 properties in Sydney's northern suburbs are without power.
The weather bureau predicted winds would strengthen throughout the day but heavy rainfall was unlikely due to fast-moving thunderstorms.
Cooler weather conditions are expected as a cold front moves through NSW from southeast parts of the country.
A dry air mass means southern parts of NSW could have temperatures drop below 20C, particularly in the Southern Ranges and South Coast region.
Gale warnings are in place for the Eden Coast and strong wind warnings for the Macquarie Coast, Hunter Coast, Illawarra Coast and Batemans Coast.
Hazardous surf warnings are also in place for the Illawarra Coast, Batemans Coast and Eden Coast, with the NSW Police Marine Area Command advising people to consider staying out of the water.
