The dispute started on April 10 when the Beijing newspaper published a report accusing Nongfu Spring of adopting the water-quality standards of Zhejiang province instead of the stricter national standards, although the water is sold all over China.

In subsequent stories, the newspaper was involved in fierce exchanges of accusations and counterattacks with the company.

Zhong Shanshan, chairman of Nongfu Spring, said at a news conference on May 6 in Beijing that the company has adopted both national standards and provincial requirements in Zhejiang, and that the national standards are mandatory for all bottled-water enterprises, which is why they are not labeled on its products.

He also said that wherever there is a discrepancy between the standards, the company has followed the stricter one.

His remarks were later endorsed by health authorities in Zhejiang, which said random checks on four batches of Nongfu Spring bottled water from its six production sites on April 11 by the quality watchdog of Hangzhou all passed tests and met national mandatory standards for bottled drinking water.

The company said in May that it had filed a defamation suit to a Beijing court, seeking 60 million yuan ($9.7 million) in damages from the newspaper.

However, whether the court received the suit has not been reported.

Nongfu's latest move was made amid a nationwide campaign by the government and news organizations to crack down on journalistic corruption and fabricated reporting.

The campaign was launched after Chen Yongzhou, a reporter at the Guangdong newspaper New Express, was detained by police in Hunan province on suspicions of taking bribes and using fake materials to denigrate a Hunan company.

The State General Administration of Press, Publication, Radio, Film and Television has called on all media organizations and reporters to learn from the case.