China Southern Airlines Co may order as many as 12 Boeing Co 777 freighters, costing as much as US$2.88 billion, to tap into the country's growing air cargo demand, said Deputy General Manager Liu Xiaoxiao.

China's largest airline plans to operate a fleet of 20 freighters within five years, Liu said in an interview with Bloomberg News in Shanghai on January 26.

The airline has two 747 freighters and announced an order for six 777 freighters last year. All of the new freighters will also be 777s, Liu said.

The decision by China Southern, the country's only Airbus SAS A380 customer, to operate an all-Boeing freighter fleet is a further blow for the delayed superjumbo program. Chinese airlines and overseas carriers, such as Cathay Pacific Airways Ltd, have added cargo capacity in China as the country's growing exports drive demand.

"Carriers are trying expand in the more profitable cargo business to gain from the economic growth," said Jack Xu, an analyst at Sinopac Securities Asia Ltd in Shanghai.

China Southern's yield from carrying cargo is about three times as much as it is for passenger traffic, Xu said.