Thai Airways International will delay the launch of  long-haul flights for its new Airbus A350 XWB while it works through the Australian regulatory process.

The A350 service to Melbourne was originally scheduled to start on September 16  but Thai Airways president Charamporn Jotikasthira said the  service would be delayed because the approval process required by Australia’s  Civil Aviation Safety Authority would not be completed in time.

Thai will continue to operate normal schedule with two flights daily to Melbourne using other aircraft.

The carrier had apparently based its estimate for the A350's maiden flight to Melbourne on the 2014 certification process for its Boeing 787, which it noted had been “much shorter”. It now expects the A350 approval to be completed in time for the start of Northern Winter Schedule at the end of October.

 "In the meantime, Thai will operate the A350 between Bangkok-Chiang Mai and Bangkok-Phuket, which will give passengers in Thailand more opportunities to experience the elegance of the Thai A350," Jotikasthira  said.

A CASA spokesman said the authority was working through the relevant regulatory and safety issues as quickly as possible but needed to ensure “everything’s done properly and thoroughly’’.

Thai took delivery of the first of 12 A350-900s at the end of last month and held a touchdown ceremony with airline and Airbus officials on August 31 at Suvarnabhumi Airport in Bangkok.

The carrier has four purchase orders for the mid-size, long-range planes and eight lease agreements, with a second aircraft to be delivered in the third quarter also slated to operate the Melbourne route.

The first plane  received the royally bestowed  name “Wichian Buri’’ and comes configured with 32 business class seats and 289 in economy all with access to high-definition video-on-demand and wi-fi.

The 32 flat bed seats in Royal Silk Class are in a 1-2-1 configuration offering guaranteed aisle access with a 16-inch touch screen.  In economy, passengers get 18-inch wide seats with a 32-inch seat pitch and an 11-inch touch screen.

The Roll Royce-powered plane, with its 25 per cent improvement in efficiency and lower maintenance costs, is expected to give Thai a competitive boost on the Melbourne route.