Thai Airways International will delay the launch of its planned Airbus A350 flights to Melbourne, originally planned for Sept 16.
THAI president Charamporn Jotikasthira on Friday attributed the delay to "additional inspections and requirements from Australian authorities" for the aircraft.
The airline said the service could be deferred to the end of October if the approval process is completed before the start of the winter schedule.
While the carrier waits for the green light from Australia, it plans to use the new aircraft on domestic routes from Bangkok to Chiang Mai and Phuket, it said without elaborating on the domestic schedule.
The first A350 acquired by the national carrier landed at Suvarnabhumi airport from the Airbus centre in Toulouse, France, on Aug 31.
THAI has ordered 12 of the long-range, widebody jets from the European planemaker, with five of them to be delivered next year.