China on Friday officially launched the world's first dual-mode mobile phones, which function in both GSM (Global System for Mobile Communications) and CDMA (Code Division Multiple Access) networks.

China Unicom, the communist nation's second largest telecom carrier, launched the first 400,000-plus dual-mode phones it purchased directly from manufacturers across the country.

The phones are expected to sell out by December, chairman and president of China Unicom, Wang Jianzhou said.

The new-type mobile phones, priced between yuan 4,500 (about $542.17) and yuan 4,800 (about $578.31), enable users to switch between the GSM and CDMA networks easily with just the push of a button.

It would allow customers to have the best of both world -- the unique features of CDMA network and the vast coverage of GSM network.

Analysts say the new product will further strengthen the competitive power of China Unicom, the world's third largest mobile operator, which currently operates China's only CDMA network and second largest GSM network.

China Unicom lags behind China Mobile, the biggest mobile communications network in China, in terms of scale and signal coverage of its GSM network.