Thousands of passengers have been left stranded at Sydney Airport after dangerous winds sparked widespread flight delays and cancellations that continued into Friday night.

Key points: Strong winds that caused Thursday's dust storm in Sydney continued on Friday

Strong winds that caused Thursday's dust storm in Sydney continued on Friday Some passengers claim they were forced to sleep in the terminal on Thursday night

Some passengers claim they were forced to sleep in the terminal on Thursday night Two of the airport's three runways are closed

At least 100 flights into and out of Sydney Airport were cancelled, with wind gusts which caused morning delays increasing into the afternoon.

Sydney Airport said multiple domestic and international flights were delayed and two of the three runways were closed due to the strong winds.

An airport spokeswoman said winds had hit 80 kilometres per hour.

"As one of the world's busiest airports, safety is out first priority," she said.

"We appreciate this is frustrating, particularly heading into the weekend.

"We are working with airlines to provide regular updates to our travelling passengers."

Sorry, this video has expired Thousands stranded at Sydney Airport

Virgin Australia, Jetstar and Qantas said the strong westerly winds in Sydney as well as storms in Melbourne were affecting all airlines.

Some passengers took to social media to vent their frustration, complaining of a lack of communication from the airlines.

But Sydney Airport said they had been making regular updates over the public announcement system in the terminals.

One passenger, Lennete, said she had been waiting at the airport for a flight to Brisbane for more than two hours.

"It's chaos," she said

"[But] it's out of my control. There's nothing anybody can do about it, the weather is the weather."

Other passengers who spoke to the ABC said they had been advised replacement flights might not be avaliable for days.

Aborted landing from LA

The conditions caused a Qantas flight from Los Angeles to abort its landing on Friday morning.

A Qantas spokeswoman said the plane circled Sydney for 10 minutes before landing safely.

In a statement Qantas said it would advise passengers if there were changes to their flights.

A mass of passengers waiting at Sydney's domestic airport. Delays are expected to continue into Friday afternoon. ( ABC News: Cameron Gooley )

The Bureau of Meteorology (BOM) earlier issued a gale warning for the Sydney coast, expecting strong winds to continue throughout Friday.

The State Emergency Service said more than 470 people had called for help in the morning across the state.

More than half of those calls came from Sydney.

Passengers sleep at terminal

Passengers who were supposed to board a Rex Airlines plane to Dubbo on Thursday night were forced to sleep in a terminal at the airport after their flight was cancelled.

Gayle Clayton, who lives two hours north of Dubbo, had surgery hours before the scheduled flight and took shelter with a group of 18 people inside the international terminal as the domestic terminal closed for the evening.

She said Rex Airlines did not offer any alternative accommodation.

She was she was "appalled" with the lack of support.

"I'm disgusted, absolutely disgusted — not even a coffee voucher, nothing," she said.

Rex Airlines has been contacted for comment.

A damaging wind warning has been issued for areas across parts of NSW, including the Central Tablelands, Illawarra, and the south coast.

"The most dangerous area to keep an eye out for is in the warning area [and] parts of the ACT and the Snowy Mountains," BOM duty inspector Jordan Notara said.