Tim Hunt (24), who lives in Manly and works in central Sydney, said he woke to find his curtains "glowing orange".
"When I pulled back the curtains I saw the sky and everything outside was just orange.
"I wasn't sure what to think of it at first, but after the initial `What the hell?' it was just amazing, like images you would expect from that little buggy Nasa has cruising round on Mars."
Mr Hunt said he usually cycled to work, but that was not possible yesterday.
But by early afternoon, the air had all but cleared and the sun was out, he said.
When Amy Cannan arrived at her office on the 32nd floor of a Kent St building in central Sydney, her usual view from Darling Harbour across the city to the Blue Mountains, had disappeared.
"It seriously looked like someone had painted the windows fluoro-orange. It was like a bright orange light was shining into the building. It was insane."
Co-workers who had lived in Sydney all their lives said they had never seen anything like it before either, she said.
"Everyone's been up taking pictures. It's just bizarre."
About 500 passengers on flights to Sydney yesterday were affected by the conditions.
Three early flights had to return to New Zealand.
Flights resumed from about 4pm as conditions cleared, an Air New Zealand spokesman said.
By later in the afternoon the dust had engulfed Brisbane, where it was being described as the "worst dust storm in a decade".
Australian meteorologist Barry Hanstrum told AAP there was "a fair chance" dust would be blown out across the Tasman.
"They may see some effects of reduced visibility as far east as New Zealand," he said.
