The Bangkok-bound QF23 took off from Sydney about midday on Friday and circled over western Sydney for up to 20 minutes before heading back to the airport.

In a statement, Qantas said there was an issue with an engine and the aircraft landed safety at Sydney airport without incident an hour after taking off.

Engineers inspected the Airbus 330-303 after it landed.

“Emergency service vehicles were on standby as is normal procedure,” the airline said in a statement.

“Passengers will be re-accommodated on another aircraft departing for Bangkok later

this afternoon.

“We thank our customers for their patience and understanding.”

Flight radar captured the Qantas flight circling several times over western Sydney before making its way back to its departure airport, an hour after taking off.