A Tigerair Airbus A320-200, registration 9V-TRX performing flight TR-2993 from Taipei (Taiwan) to Singapore (Singapore) with 163 people on board, was enroute at FL350 about 230nm southeast of Ho Chi Minh City (Vietnam) when the crew decided to divert to Ho Chi Minh City due to a burning odour in the forward cabin. The aircraft landed safely about 35 minutes later. A replacement A320-200 registration 9V-TRD was dispatched to Ho Chi Minh City, resumed the flight and reached Singapore with a delay of 7.5 hours. The airline reported the aircraft was grounded for an examination by maintenance after a burning odour was detected in the cabin.