Music industry representatives have warned advertisers to stop supporting Baidu, China's largest search engine, because they believe it is encouraging music piracy.
Baidu is the largest source of pirated music in China, according to the representatives, who describe the company as "incorrigible".
The Chinese firm's music search engine is accessed through what is described as a prominent link on the company's home page
Baidu provides links only to music files stored on third-party servers. No music is stored on computers owned or controlled by Baidu.
The music industry bodies behind the move include the International Federation of the Phonographic Industry (IFPI), the Music Copyright Society of China and the newly-formed China Audio-Video Copyright Association.
These organisations represent a variety of major international and domestic labels.
Warner Music representative Monica Lee claimed at a press conference in Beijing yesterday that about 80 per cent of potential music industry revenue in China is lost to piracy.
Some piracy is to be expected, Lee admitted, but current levels are unacceptable.
Baidu takes almost a quarter of all sales in China's rapidly expanding online advertising market, according to local analysts.
Google, the world's largest search firm, ranks fourth with almost 10 per cent of the country's total online ad revenues, researchers from Analysys International said last year.
The IFPI is currently demanding $9m in damages from Baidu in a copyright lawsuit filed earlier this year.
Baidu reporter $81.9m in revenues in the first quarter.