China Eastern Airlines Corp Ltd and China Southern Airlines have launched a comprehensive tieup in aircraft purchasing, ground services and marketing, the official Shanghai Securities News reported.

Li Fenghua, chairman of China Eastern Airlines, said the tieup was not influenced by the recent offer by China National Aviation Corp (CNAC) to take a stake in China Eastern.

The companies said the tieup is not exclusive.

Liu Shaoyong, chairman of China Southern, the country's largest airline by fleet size, was quoted as saying that China Southern is monitoring merger developments in the industry "but will only act when it concerns China Southern's core interests."