China’s largest internet firm, Tencent, is reportedly now censoring messages sent by international users of its popular WeChat service.

The Shenzhen-based web giant, which accrued $US1.8bn in revenues in the last quarter, is one of the few Chinese online companies trying to expand its footprint overseas.

Although its QQ instant messaging service has around 800 million domestic users and its web portal of the same name is one of China’s most popular, the Whatsapp-like platform WeChat (or Weixin) is its most prominent product beyond the Middle Kingdom.

It has now emerged that messages sent between users outside China will be blocked when they contain certain words.