Tencent says that users who were not able to send messages were experiencing a technical glitch.
Chinese Internet service portal, Tencent dismissed claims that messages sent on its app, WeChat were being censored.
Tech in Asia and The Next Web reported to have received messages that their chat entries contained "restricted words".
Tech in Asia also found that words censored globally for WeChat users, including Southern Weekend, the Chinese name of a newspaper currently battling the Chinese government over censorship.
The NextWeb found that WeChat would also not allow users to mention "Fulun Gong", a group that the Chinese government has banned in the country.
"A small number of WeChat international users were not able to send certain messages due to a technical glitch [last] Thursday," Tencent toldTech in Asia
"Immediate actions have been taken to rectify it. We apologize for any inconvenience it has caused to our users. We will continue to improve the product features and technological support to provide [a] better user experience."
WeChat enables users to easily communicate with each other an any mobile device they use and has about 300 million users in 100 countries and regions.
A total of 400 million people accessed Olympics coverage online through Tencent technologies for the London 2012 Games.