Tencent Holdings Ltd, China's largest Internet firm by market value and users, yesterday said net profit in 2012's fourth quarter rose 37 percent from a year earlier to 3.46 billion yuan (US$557 million) as online advertising income boomed.

Tencent said it will leverage the booming mobile Internet to expand its products to reach more users at home and abroad.

"We will extend our communications and social leadership from personal computer to smartphone via applications such as Wireless QQ and WeChat and integrate additional services like content applications and games to enhance user experience of WeChat," Tencent founder and Chairman Pony Ma said.

Launched in early 2011, WeChat allows smartphone users to send text and voice messages, and its user base had topped 300 million by January.

Tencent's sales in the three months ended on December 31 surged 53 percent to 12.2 billion yuan, it said in a stock exchange filing yesterday. Sales at its Internet value-added service unit, which includes online games, rose 32 percent to 8.5 billion yuan from a year earlier. Online advertising revenue increased 58 percent to 947 million yuan.

Its profit last year jumped 24.8 percent to 12.7 billion yuan on a 54 percent surge in revenue to 43.9 billion yuan.