Winds gusting up to 70 kmh (44 mph) also fanned major bushfires along the east coast, threatening homes and forcing evacuations.
Sydney Airport cancelled 76 flights after all but one runway was closed due to the strong winds.
“It’s not safe to have flights landing or departing and as a result we are going to a single runway, there are delays,” Sydney Airport told Reuters.
Melbourne Airport also reduced the number of flights allowed to arrive and depart each hour due to Sydney Airport cancellations.
The strong winds fanned fires across New South Wales state, with Australia’s Rural Fire Service reporting 21 fires.
“(This) was the first operational drop that its done in the world...it has proven to be effective,” Chris Garlick, a spokesman for the NSW Rural Fire Services told Reuters.
Fires around the popular tourist spot of Port Stephens, nearly 200 km (124 miles) north of Sydney, forced an emergency evacuation of residents. There were no reports of injuries or loss of property. Emergency workers warned the strong winds threaten to escalate the fires.
The strong winds are part of a massive weather system over southeast Australia, that whipped up a 500 km (310 miles) dust storm on Thursday, which swept across the drought-pratched interior to blanket Sydney.
The Australian Bureau of Meteorology said winds would ease by Friday evening, offering some respite to travellers and fire fighters.