Almost 50 flights cancelled at Sydney Airport as dangerous winds hit

Almost 50 flights have been cancelled at Sydney Airport so far after wind gusts forced the airport to confined traffic to a single runway.

Gusts of up to 70km/hr are expected to sweep Sydney Airport today, peaking between 9am-3pm.

Major airlines have all been forced to cancel multiple flights, leaving some passengers stranded ahead of the NSW school holidays.

As of 7am, Airservices Australia said it had confined traffic to one runway.

"This decision is purely weather and safety-related," a spokesperson said.

Westerly winds of up to 37km/hr have made parallel runway operations unsafe.

It's expected the single-runway policy could be enforced for much of the day.

There are fears flight cancellations could therefore continue, potentially reaching up to 100.

It follows disruptions at multiple airports yesterday that were blamed on a number of air traffic controllers taking sick leave, particularly in Brisbane. But 9News understands the delays today are unrelated.

Qantas said at least 100 flights yesterday were delayed, leaving thousands of passengers impacted.

A total of 10 of the airline's flights were cancelled outright.

Virgin said its affected flights were mostly across Brisbane, the Gold Coast and Ballina.

Most of the delays took place from about 6am with knock-on effects through to 1pm, covering the busy morning and lunchtime rush.

Adding to the potential for chaos today and across the weekend is the beginning of the NSW school holidays, with today being the last day of term.

Already a number of flights across Virgin and Jetstar have been cancelled this morning.

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