The Paris-based press freedom group said it had created a virtual garden that is 'dedicated to freedom of expression' during the Expo, which runs from May 1 to October 31.
Visitors to the www.rsf.org website can use Chinese, French and English to explore the 'cyber-police pavilion, the Tibet pavilion and the prisoners of conscience enclosure, where they will be able to sign petitions for (the prisoners') release,' the group said.
'The Garden of Freedoms will be the only place in the Shanghai World Expo where you will be able to discover the realities that the Chinese authorities go out of their way to hush up,' it said.
It said the Chinese consulate in Paris had refused to issue visas for two Reporters Without Borders employees who wanted to attend the Expo.
The Hong Kong-based China Human Rights Defenders last week said Shanghai authorities had sent at least 10 local rights activists to labour camps and detained or placed under house arrest dozens of others to prevent them staging protests during the Expo.
Hundreds of thousands of police and security guards, aided by some two million 'civic volunteers,' are ensuring public order in Shanghai during the Expo.
Reporters Without Borders criticized French President Nicolas Sarkozy and other international leaders scheduled to attend the opening of the Expo for failing to raise the 'dark side' of rights abuses in China.
'A World Expo is meant to bring people together around such values as progress, humanism and culture,' the group said.
'What kind of universal values is China offering us when it jails such advocates of democracy as the intellectual Liu Xiaobo?,' it said, referring to a dissident writer who was sentenced to 11 years in prison for subversion in December.
The group said it had raised its concerns in a letter to the Paris-based International Bureau of Exhibitions, which approves and oversees international and World Expos, but it received no reply.
The Shanghai Expo is designed to 'explore the full potential of urban life in the 21st century,' with the theme 'Better City, Better Life.'
Organizers aim to attract a record 70 million visitors, most of them Chinese.