Cyclone-strength winds have wreaked havoc across NSW, shattering windows, tearing off roofs and causing airport and train chaos, leaving hundreds stranded.
The Bureau of Meteorology issued a severe weather warning for parts of NSW early on Friday with gusts in excess of 100km/h recorded later in the morning.
NSW Ambulance was called to International House Sydney at Barangaroo before midday on Friday following reports three windows shattered in a tower block, and fell up to five storeys.
The building was evacuated but there were "no patients", an ambulance spokeswoman said.
Building owners Lend Lease said the incident occurred "due to high winds".
"The area has been cordoned off and emergency services are in attendance," a spokeswoman said in a statement.
Northbound train commuters were stranded on the Sydney Harbour Bridge, between Wynyard and Milsons Point, after panels on the building broke apart and "impacted a train", Fairfax reported.
The BOM warning came after two walls at separate Sydney building sites collapsed on Wednesday in high winds.
One 30-year-old worker was killed and a teenager was rushed to hospital with critical head injuries.
The SES on Friday received 330 calls for help with winds so strong they blew the roof off a business in Wollongong, requiring 80 people to be evacuated.
Elsewhere, emergency crews scrambled to restore power to more than 40,000 homes in Sydney's south after the winds affected substations in Cronulla and Kirrawee.
Gusts of up to 93km/h were recorded at Sydney Airport with officials confirming flights had been delayed, and aviation experts describing planes forced to make second attempts at landing.
Passengers were advised to check with their airlines or updated flight status pages.
Motorists on the Sydney Harbour Bridge also faced delays after the winds damaged railway infrastructure and forced the closure of two northbound lanes.
The extreme conditions also forced the animals at Symbio Wildlife Park, in Sydney's southern suburbs, to hold on tight and take shelter to avoid being blown away.
"Red Pandas climbed down from their trees and took shelter below, the koalas went into their protected areas, the cheetahs got down as low to the ground as they could, the monkeys either huddled together or went into their nest box," a park spokesperson said.
"The brave little meerkats faced it all head on and the kangaroos all bounded away to see shelter against the bushes."
The wild winds are expected to ease on Friday evening but will be back on Saturday, before gradually easing over the weekend, a Bureau of Meteorology spokesman said.