Chinese websites are already among the world's most censored, with Beijing blocking many foreign Internet services with a system known as the "Great Firewall of China".
Regulations posted on a government website, set to go into force next month, state that foreign firms "are not to engage in online publishing".
The regulations define online publishing as the provision over the Internet of books, maps, music, cartoons, computer games and "thoughtful text", as well as other content.
The State Administration of Press, Publication, Radio, Film and Television (SAPPRFT), which issued a draft of the rules, could not immediately be contacted by AFP.
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The regulations say any Chinese publishers cooperating with foreign firms to provide online content would need prior approval from the body.
Chinese publishing expert Xu Yi told AFP that the implications of the rules were unclear.
"I think these regulations provide a legal basis for the government to manage foreign companies setting up websites in China," he said.
Writing on the website Tech In Asia, veteran China watcher Charles Custer said the rules were an attempt by SAPPRFT to play a bigger role in content management, previously seen as the domain of other government agencies.
"SAPPRFT has traditionally been a regulator of offline publications, but it has increasingly been flexing its online muscles over the past decade, and occasionally clashing with other censorship organs," he said.
"In practice, the new regulation isn't likely to change much beyond adding another hurdle would-be publishers have to jump through," he added.
Authorities have proposed a new law to control the activities of foreign non-governmental organisations, while state media have warned of "hostile foreign forces" said to be using them to foment revolution.
In recent years, censors in Beijing have moved to ban certain TV shows and movies from abroad from being shown online and authorities have decried "Western" influence on the country's educational system.