BEIJING—China is considering new Internet rules that would pressure service providers to cut off access to foreign websites, adding to the government’s growing legal framework bolstering its control of cyberspace.

The proposed rules would prohibit the country’s Internet-service providers from allowing connections to websites with domains, or Web addresses, registered outside China. Violators would face fines of up to 30,000 yuan ($4,621) and public notices exposing their failure to obey.

The new guidelines are part of a set of draft revisions to Chinese regulations on the management of Internet domain names, posted for public comment on a government website Monday afternoon.

If fully implemented, the regulations would effectively wall off the world’s most populous country from vast swaths of the Internet. Other, similar rules have been weakly enforced in the past, but with Chinese President Xi Jinping dramatically tightening political controls, it is unclear how meaningful the changes would be, analysts said.

“They can always backtrack since it’s vague and enforcement is sometimes lax, but given the current climate, it seems to be in line with the increasing crackdown on press and Internet freedom,” said Lokman Tsui, an expert in media and technology policy at Chinese University of Hong Kong.