The additional Boeing 737-800 aircraft are for the flag carrier's domestic service and for delivery during 2014, the company said in a statement, adding that leases on two existing B737-800s would be extended this year.

"The refurbished aircraft will give Qantas International a truly world-class product in global aviation's most dynamic and competitive market," chief executive Alan Joyce told a press conference.

"Growing with Asia is a major priority for the Qantas Group and this investment underpins our commitment to the region."