Amnesty International is calling for the Chinese government to release 33 prisoners.
Residents of one Chinese province must swipe access cards containing personal data on an identifying machine before they can get on a PC to access the Web.
Internet cafes must keep records of what information and sites customers visit for two months.
The search engine has been blocked from Chinese ISPs for several days, sources said.
The number of Chinese regularly using the Internet has soared by 72 percent in one year.
The portals agree to implement strict limits on what sort of content, sites they provide to users.