Top Chinese filmmakers have called on China’s annual parliament, the National People’s Congress, to bring in greater efforts to control “rampant” film piracy, which they say is hampering the domestic biz’s efforts to grow. And senior voices in the biz are calling for a film law to stamp out on-screen rape and murder.

“Boosting copyright protection is key to the healthy development of the film industry and the prosperity of the cultural market,” said top Chinese helmer Zhang Yimou, a member of the advisory panel that accompanies the National People’s Congress, the Chinese People’s Political Consultative Conference (CPPCC).

Zhang, currently lensing “13 Flowers of Nanjing” with Christian Bale, submitted a proposal for tighter control of piracy to the CPPCC, along with five other members, including fellow helmers Feng Xiaogang, Yin Li, Feng Xiaoning and Chen Guoxing, and the Beijing Film Academy president Zhang Huijun, the People’s Daily reported.

The proposal says that although China has notched up progress in protecting intellectual property rights, film piracy and unauthorized broadcasting were still rampant, even getting worse, frustrating filmmakers.

The annual congress largely has the role of giving rubber-stamp approval to bills decided by the Communist Party leadership, but it can provide a forum for debate on some of the more contentious issues affecting China. It is taking place in the Great Hall of the People near Tiananmen Square downtown.

Zhang made his name on the arthouse circuit abroad with “Raise the Red Lantern” and “Red Sorghum,” earning him the ire of the government. He subsequently made movies widely seen as pro-government allegories, such as “Hero,” and orchestrated the bombastic Olympic Games opening ceremony in August 2008.

China’s 2010 B.O. was more than $1.5 billion, according to the State Administration of Radio, Film and Television, but piracy remains a major issue in China. The number of pirate DVD shops is ebbing, but piracy downloads are increasing, despite regular, highly public efforts to crack down.

Zhang said that some home movies with fairly good B.O. were forced to withdraw from cinema in less than two weeks as many were copied two or three days after their bows.

Yin Li called on the NPC to give state funding to filmmakers to carry out technological research and upgrading so that film piracy could become technologically impossible.

Zhang Huijun called for a ban on the depiction of murder, rape and violence in movies.

“There should be detailed legislation for the film industry to regulate what level of violence and bloody content is allowed in a movie, and to forbid scenes concerning murder and rape,” said Zhang, president of the state-run Beijing Film Academy, which has produced most of the country’s top helmers.

China has no film classification system, despite regular calls to replace the censor’s scissors with reliable and predictable classifications, thus allowing directors and producers to take more risks.

But Zhang said: “China needs a film law more than a classification system.”

He also said China needed more cinemas built or renovated, especially in second and third tier cities, to curb the growth of piracy.