"Reporters Without Borders condemned the latest Chinese effort to gag the Internet by means of directives to portals that have discussion groups," the group said in a statement on Sunday.
"Discussion forums are used by millions of Chinese and, although closely monitored, they at least offered an outlet for popular discontent and criticism, but we fear these latest measures will just make Internet users censor themselves even more."
China's cultural minister Sun Jiazheng last week called for tighter controls on the internet, including 24-hour surveillance, and urged users to join in on the government effort to police the web.
"Managing Internet bars requires centralised measures, the people's prevention and monitoring and thorough control," Sun was quoted as saying by Xinhua news agency.
Internet use rises
Despite government restrictions, China is second only to the United States for the number of people online. The number of users rose to 79.5 million by December 2003 from 59.1 million in December 2002 - up by 34.5%.
Reporters Without Borders said that since new regulations on internet chatrooms were issued on 23 February, many news groups had been shut down and the filtering of online messages stepped up.
"It also seems that debates of a political nature have virtually disappeared from forums as a result of stricter filtering criteria used by the Ban Zhu (discussion group moderators)," it said.
"Discussion forums are used by millions of Chinese and, although closely monitored, they at least offered an outlet for popular discontent and criticism. But we fear these latest measures will just make Internet users censor themselves even more."
Reporters Without Borders
"At the same time, there has been a surge of posts by Internet users complaining about censoring of their messages, which they are unable to post online."
The media watchdog group also questioned a move by the US-based domain name management group VeriSign to assign China a DNS (domain name server), a move the group said would give Chinese internet police the ability to render unwanted web addresses inaccessible.
"The Chinese authorities regularly use DNS hijacking, a technique that makes a site completely inaccessible by redirecting its domain name to a false IP address, resulting in an error message such as 'site unavailable'," the group said.
"Verisign's decision to involve China in the management of global Internet traffic appeared extremely dangerous."