United Airlines flight returns to Sydney 'after mid-air bird strike'

A United Airlines plane has made an emergency landing at Sydney Airport, after a mid-air bird strike.

Flight 840 had departed Sydney for Los Angeles at 9.45am and was forced to turn around 45 minutes later, and landed just after 11am.

Emergency crews including firefighters were on the tarmac ready to attend to the Boeing 777.

In a statement, United said they were working to rearrange travel plans for passengers.

"United Airlines flight UA840 from Sydney to Los Angeles on Monday, 4th July returned to Sydney International Airport right after take-off due to a possible bird strike.

"United Airlines confirmed the aircraft safely returned to the airport at 11.13am, and the flight has been cancelled. United Airlines is currently working to re-accommodate passengers on the next available flight and apologise for any inconvenience this may have caused."

A map from aircraft tracking website Flightradar24 shows the aircraft circling several times off the New South Wales coast before it re-landed.

It is believed the aircraft had to dump a significant amount of fuel before it could land.