A code of conduct addressing how major Internet service providers and portal operators should deal with Internet censorship in China is in the final stages of preparation by Human Rights Watch and the providers, the head of the human rights pressure organization said Tuesday.

The code is due in the next couple of months and comes in the run up to the Beijing Olympic Games that begin in August.

Human rights in China is increasingly in the spotlight in the run up to the games, including issues surrounding censorship and freedom of expression online. The latest example of such came earlier this week when access to YouTube and Google News was blocked in the aftermath of pro-independence riots in Tibet.

Also gaining more attention is the role that foreign, mainly western, companies play in helping the government block Web sites and track down those alleged of wrongdoing online.

"One of our concerns is the degree to which the major international Internet companies have become complicit in this censorship of the Internet," said Kenneth Roth, executive director of New York-based Human Rights Watch at a Tokyo news conference.

Roth said that these companies are often blocking access in anticipation of requests from the government rather than waiting for the requests themselves. They also test the so-called "great firewall," the Internet filter that governs the complete flow of Internet traffic in and out of China, and block traffic that has been cut off by the firewall.

"We are currently working with a number of them to develop a code of conduct that would minimize that complicity," he said.

In the past several major Internet companies have been singled out for their actions in China.

Google, Yahoo, and Microsoft have perhaps taken the most heat.

Yahoo handed over information that helped authorities identify and track down dissidents that either posted online or used e-mail to send sensitive information. The most famous case is that of Shi Tao, a journalist who was jailed for 10 years in 2005. Microsoft's MSN shut down a blog following a government request, and Google offers a censored version of its search engine designed for China.

"The Internet is a real positive force for freedom. It greatly facilitates the ability of people to communicate with each other, to organize autonomously to learn about the world without government censorship," said Roth. "But just as it is an instrument of freedom, it is a target of repression. I think in this respect the Chinese government is setting the standard on control of the Internet."

Roth, who was in Tokyo to announce plans to open a local Human Rights Watch office in Japan, said all of the major foreign Internet companies operating in China were taking part in compiling the code of conduct.