A US based software producer yesterday filed a $2.2 billion lawsuit against the Chinese government, two Chinese software markers and seven major computer manufacturers for their distribution of the Internet filtering software "Green Dam Youth Escort" - which the company claims is pirated from a similar product it makes.

Cybersitter, a family-owned software firm based in Santa Barbara, filed the lawsuit in a Los Angeles federal court, alleging that the two software makers of Green Dam illegally copied over 3,000 lines of code from its award-winning Internet content filtering software.

Zhengzhou Jinhui Computer System Engineering and Beijing Dazheng Human Language Technology Academy co-developed Green Dam - an Internet filtering software designed to block violent and pornographic content on the Internet to protect minors - after winning a 417-million-yuan ($61 million) bid from the Ministry of Industry and Information Technology (MIIT).

But users had repeatedly raised concerns about the security loopholes of Green Dam, which could be exploited by hackers.

Additionally, the complaint alleges that the PC makers - Sony, Lenovo, Toshiba, Acer, ASUSTeK, BenQ and Haier - cooperated with the Chinese government and other software manufacturers to distribute 56 million copies of the software after they were aware that the program's content filters were possibly stolen from Cybersitter.

The MIIT had required both domestic and overseas PC makers to include the software with their PC packages sold in China by July 1 last year, but the government decided to indefinitely delay the mandatory installation of the software the night before the directive went into force.

The delay came after some PC makers voiced concern about the short notice given to them for the software installation.

"This lawsuit aims to strike a blow against the all-too-common practices of foreign software manufacturers and distributors who believe that they can violate the intellectual property rights of small American companies with impunity without being brought to justice in US courts," Cybersitter's attorney Greg Fayer said in a statement sent to China Daily.

The MIIT could not be reached to comment.

A spokeswoman for Lenovo, China's largest PC maker, told China Daily that the company has not shipped Green Dam with PCs for several months.

"We only include CD-ROMs containing Green Dam with our PCs or save the installation file of the software on the hard drive of the PCs; it is up to the users whether to install the filter or not," she added. "We never pre-installed Green Dam on any computer."

The other PC makers mentioned by Cybersitter's attorney could not be reached for comment.

Zhang Chenmin, manager of Zhengzhou Jinhui Computer System Engineering, could also not be reached yesterday.