China has defended its tight controls on the internet, saying it has no intention of relaxing its censorship of websites it deems subversive or a threat to national unity.

In a white paper published on Tuesday, the government also said it would not accept outside criticism of its internet controls and warned foreign governments and companies to respect its rules.

"Within Chinese territory, the internet is under the jurisdiction of Chinese sovereignty. The internet sovereignty of China should be respected and protected," the paper said.

It added that China "advocates the exertion of technical means" in line with existing laws and international norms "to prevent and curb the harmful effects of illegal information on state security, the public interest and minors".

'Great Firewall'

The paper said such laws allowed the curbing of online content on topics ranging from "instigating racial hatred or discrimination and jeopardising ethnic unity" to gambling, violence and obscenity.

Google announced in March that it would pull out of China over web censorship [AFP]

China is believed to operate one of the world's largest and most sophisticated systems of web censorship, which has been dubbed by some the "Great Firewall of China".

Backed by what analysts estimate is a force of several thousand cyber police, the system monitors and blocks access to any content the government deems unacceptable, ranging from pornography to political dissent.

The release of the white paper follows a high profile spat earlier this year with internet search giant Google over the issue of online censorship.

In March Google announced it was pulling out of China after failing to reach an agreement with Chinese that would allow it to continue working in the country.

The row in turn touched off a war of words with the US over internet freedom, at a time when ties were already frayed over US arms sales to Taiwan, a visit by the Dalai Lama, and a host of trade and currency issues.

Jailed

According to the New York-based Committee to Protect Journalists, China is one of the world's most oppressive nations in its approach to online censorship.

As of last December, the group said, China had jailed at least 24 journalists, many of them on charges related to internet blogging.

However in Tuesday's white paper China insisted it "guarantees the citizen's freedom of speech on the internet as well as the public's right to know, to participate, to be heard and to oversee".

The paper added that China's leaders "frequently log onto the internet to get to know the people's wishes" and participate in online chats with users.

The report said there were 384 million internet users in China at the end of 2009, equal to about 29 per cent of the total population, and said it wanted to increase that figure to about 45 per cent in the next five years.

It said a key goal would be to push the internet into rural areas where the paper said there was a "digital gap."