A top Beijing official called for stronger management of the Internet Wednesday at a government-organised conference condemned by rights campaigners as a Chinese attempt to promote its online controls globally.

China, which censors online content it deems to be politically sensitive, opened the World Internet Conference in Wuzhen with the country's biggest Internet companies in attendance alongside a sprinkling of foreign executives and officials.

Participants at the three-day conference in the tiny eastern Chinese town have unfettered Internet access to sites denied to the rest of the country, such as Facebook and Twitter, attendees said.

As well as the social media giants, Beijing blocks some Western media websites including the New York Times and search engine Google, among others.

Vice Premier Ma Kai, the highest-ranking Chinese official attending, said the Internet could help spur the healthy development of the world's second largest economy but made clear the medium should be under control of the state.

"The Chinese government will strengthen administration of the Internet under the law," Ma said.

"A well-managed Internet concerns state sovereignty, dignity and development interests, and international security and social stability," he said.

Ahead of the conference, rights group Amnesty International described the gathering as a chilling attempt by Beijing to promote its own domestic Internet rules as a model for global regulation.

China imposes strict limits on freedom of expression, and rights groups say it uses state security as a pretence to crack down on political dissent.

"China appears eager to promote its own domestic Internet rules as a model for global regulation. This should send a chill down the spine of anyone that values online freedom," William Nee, China researcher at London-based Amnesty, said in a statement.

Ma also called for cracking down on crime and terrorist activities making use of the Internet, as well as joint efforts to thwart cyber attacks.

- 'Elephant in the room' -

China and the United States have traded accusations of state-sponsored cyber-spying, with Washington in May charging five Chinese military officers for breaking into US computers for industrial espionage purposes.

The head of China's powerful State Internet Information Office, Lu Wei, dangled the promise of the world's largest Internet market before the companies attending.

"China has a population of over 1.3 billion and an Internet population of over 600 million," he told the opening ceremony. "I hope everyone can find a market here and seize business opportunities."

Amnesty urged business leaders at the conference to speak out for online freedom and "challenge the Chinese government's shameful record", with Nee adding: "Human rights should not be the elephant in the room."

Foreign company representatives attending include the executive chairman of networking site LinkedIn, Reid Hoffman, and Facebook's vice president for corporate development Vaughan Smith.

LinkedIn launched a Chinese version of its site earlier this year, which unlike its English-language counterpart does not allow group discussions.

Facebook has an office in Hong Kong, where it is not blocked, and has also reportedly rented office space in Beijing in a bid to boost its business selling online ads to Chinese companies and local governments seeking to promote themselves abroad.

Its founder Mark Zuckerberg has been learning Chinese and impressed observers last month when he conducted a 30-minute Q&A session in Mandarin at a top Beijing university.

Jack Ma, founder of e-commerce giant Alibaba which recently listed on the New York Stock Exchange, told the conference the Internet had "deeply influenced and changed Chinese society and the economy in all aspects".