"We will strengthen the blocking of harmful information from outside China to prevent harmful information from being disseminated in China and withstand online penetration by overseas hostile forces," Wang Chen of the Cabinet's Information Office told Chinese state-run media Xinhua today.
The move is the latest in an enduring campaign to restrict access to information which may criticise or otherwise negatively impact the Chinese government.
China's 400 million-plus internet users are already denied access to websites run by political and human rights activists and some news organizations.
China employs a significant workforce, commonly called cyber-nannies, to trawl the internet for "subversive" content to erase or block access to and spread government propaganda.
The announcement follows the adoption of an amendment to China's Law on Guarding State Secrets on 29 April which required telecommunications and internet companies to report customers who reveal so-called "state secrets", a term which was not elucidated in the amendment.
Though Internet search giant Google Inc. left the country short after a series of Chinese cyber attacks, the new law might impact foreign companies in China such as Yahoo! Inc. and Microsoft Corp.