Flights must be booked between 4 December & 17 December 2013 and be for travel between 14 January & 3 April 2014. 20% off discount offer applies to the base fare portion of the total fare and discount is not applied to the taxes and surcharges portion of the total fare. Offer applies to all D7 flights operated by AirAsia X Berhad. AirAsia X's standard terms and conditions of carriage apply, for details see airasia.com
Just to clarify this only applies to flights to and from Australia and not internal Asian flights.