The freight section of China's largest airline, Air China, has become an independent carrier, the Xinhua-run Economic Information Daily said on Tuesday.

The new Air China Air Cargo Ltd would be the fourth independent cargo carrier in China with Sino-Singaporean joint venture Great Wall airfreight company, Jade Cargo International, and Shanghai International Cargo Airlines.

Great Wall officially went into operation at the end of last month, while Jade Cargo International and Shanghai International Cargo Airlines were both scheduled for operation in coming months, the paper reported.

It is expected that in the next two decades, China's airfreight volume will maintain an annual growth rate of over 10 percent, higher than the world average of 6.2 percent.

Under China's commitments to the World Trade Organization, the government was allowing foreign investors to enter China's express delivery market.

About half of China's domestic airfreight market was controlled by overseas airlines, including Lufthansa, Singapore Airlines and Korean Airlines, the newspaper said.

Air China Air Cargo Ltd and the China Cargo Airlines Ltd, a subsidiary of China Eastern Airlines, shared a third of the domestic market.

Industry insiders said if the two leading Chinese air freighters merged, the new carrier would be the largest cargo carrier in China, and the fifth largest in the world.

The two giants were still discussing cooperation proposals.

It has been reported that a cooperation agreement just reached between Air China Air Cargo Ltd and Hong Kong-based Cathay Pacific Airways could influence cooperation between the two mainland carriers.