Chinese regulators have banned the country's journalists from sharing information they have obtained on the job with overseas media or publishing it in any venue outside the media they are employed, in a move that critics say will further stifle press freedom.

The regulations, which were detailed in a June 30 document but released this week, come at a time when Chinese journalists have been accused of using their positions to blackmail. But the rules will also impact journalists who, frustrated with tight news controls over what they can publish in their own companies, sometimes release information they have obtained to outlets outside mainland China or in social media, such as their personal blogs.

In an explanatory note, the State Administration of Press, Publication, Radio, Film and Television said those acts have "disturbed the normal news order" and hurt the interest of the ruling Communist Party as well as China's national interest.

Invoking laws on national secrecy, intellectual property rights and labor contracts, the State Administration of Press, Publication, Radio, Film and Television said Chinese journalists accredited to work for state media shall not provide information to overseas news outlets as special contributors or release information in venues such as blogs, microblogs, forums or seminars.

Chen Min, a former Chinese journalist, said the new rules will "undoubtedly" clamp down on freedom of information in China, where the government has long maintained tight controls over media outlets but journalists have sought ways to break down the barriers.

"This in essence is depriving the right of the public to know," said Chen, who now works as an independent commentator and a visiting scholar in Taiwan.

He said Beijing has vaguely defined laws on state secrets, making it easy to punish journalists the government says have overstepped the rules.

"To put it bluntly, you now can only say what's sanctioned by China's propaganda officials," Chen said.

The lack of media freedom is accompanied by an environment where some reporters solicit bribes in return for not running stories that may embarrass a company or person.

The release of the regulations came a day after a British government report on Hong Kong expressed "serious concerns" about press freedom and self-censorship in its former colony.

The six-monthly report, presented by Foreign Secretary William Hague to the British parliament on Thursday, is more explicit than London's recent summaries, reflecting rising tensions over democratic reform in the Asian financial hub.

It details a series of recent incidents, including the stabbing in February of Kevin Lau, the former chief editor of a leading local newspaper, Ming Pao. It also notes media reports that London-based banks HSBC and Standard Chartered were among institutions that had pulled adverts from the popular Apple Daily tabloid "in response to political pressure."

Both banks, asked in London for comment, said any changes made in their advertising would be for commercial reasons.

Wire services