The Chinese government encourages web use for commerce and education, but blocks access to online material deemed obscene or subversive.
It reportedly operates an online police force numbering in the tens of thousands to monitor internet activity and block sites officials consider unsuitable.
In April, China launched a crackdown on online pornography after the Chinese president ordered the authorities to promote a "healthy online culture".
Hu Jintao said officials needed to "raise the level of guidance online" to protect the stability of the state.
His comments came at around the same time as a report by the Beijing Reformatory for Juvenile Delinquents which said that 33.5 per cent of its detainees were influenced by violent online games or erotic websites when they committed crimes such as robbery and rape.
Earlier this year the government launched a crackdown on the transfer of licences after it said some of those given licences, including schools, were renting or selling them.
China has the world's second-largest population of internet users, numbering some 137 million people in 2006, up 23 per cent on the previous year.
Its 120,000 internet cafes are particularly popular with customers who spend hours playing online games that link multiple competitors.
Given current rates of growth, China is expected to surpass the US as the largest online population in two years.