China has some of the tightest media restrictions in the world
China has intensified efforts over the past year to control what the media can say, a report by the International Federation of Journalists (IFJ) says.
It says hundreds of regulations have been introduced since the Beijing Olympics in 2008 to restrict reporters writing on social unrest or scandals.
Journalists were told they could only use the official Xinhua news agency during the 2008 tainted baby milk row.
They were also told not to travel to report on the Sichuan quake in 2008.
Other restrictions included a specific prohibition of topless photographs of actress Zhang Ziyi on a Caribbean beach, according to the IFJ report released in Hong Kong.
It adds that China particularly targeted online media and chatter, often refusing online journalists official accreditation.
Social networking sites organising public protest gatherings have particularly unnerved the Chinese authorities.
Foreign journalists encountered violence and their equipment was destroyed in some cases, according to the report.
But it adds that while the government has had some success in stopping information leaking out about social unrest, it is struggling to stop commentary from reaching the outside world.
China has so far made no public comment on the IFJ report.