The latest box-office hit Sacrifice has earned 58-year-old director Chen Kaige, one of the nation's top directors, more than 195 million yuan ($29.5 million) since it opened in early December, but accusations from the film's scriptwriters have raised more than a few eyebrows.

The two scriptwriters said, just hours before the film's premiere, they were disappointed that Chen had substituted his name for theirs as "writer" in the film's credits.

One of them, Gao Xuan, said she and her partner had worked with Chen for 10 months, penning most of the storyline, but had not been officially acknowledged.

Chen Hong, the director's wife, and also the movie's producer, denied the accusation and claimed her husband was entitled to name himself as writer and that this was in keeping with legal advice.

Gao responded: "It's not personal and we are not complaining but urge more respect for scriptwriters."

Chen is not the only Chinese director to be accused of plagiarism after Zhang Wenyu, a little known writer in Zibo, Shandong province, accused comedy director Feng Xiaogang of copying his story for Assembly, and sued Feng in 2008.

Although Feng won the lawsuit, the case served as a warning that Chinese scriptwriters were prepared to fight for their rights.

In November, two nationwide forums, held in Shenzhen, Guangdong province, and Hangzhou, Zhejiang province, brought together top Chinese screenwriters to discuss ways to overcome the injustices they faced.

Their main grouse is that their copyright is often disregarded and unfair clauses are forced on them by film and TV series producers. Either their names are removed from the final credits without notice, or the producers do not pay on time.

Zhao Chen, a 26-year-old TV scriptwriter, working for a video production house in Tongzhou district, Beijing, said that more than 90 percent of screenwriters are not paid in full by producers.

"You can forget the pending amount if they have already paid you 70 percent," she says, adding this is the industry norm.

Zhao says payments vary wildly - from 2,000 yuan ($307) to more than 100,000 yuan per episode.

In 2008, screenwriter Zhang Yawen received 120,000 yuan for her contribution to a movie titled A Chinese Woman at Gestapo Gunpoint, but only after a seven-year lawsuit that cost her at least 80,000 yuan.

"Few writers resort to legal means for their dues as they cannot afford it," Zhao says.

In 2009, some 20 big names in scriptwriting, including Shi Kang and Wang Hailin, co-founded a screenwriter company, to protect writers' interests.

A top screenwriter can currently make about half of what a top director makes or just one-fourth to one-fifth of what top actors or actresses make, Wang says.

However, Zhang Jizhong, a well-known director and producer, dismisses such concerns saying a screenwriter's job is only one part of the whole process.

An industry source, surnamed Xu, told Beijing-based Mirror Evening News in July, that the country produced 359 TV series with more than 10,000 episodes in 2009 and the number of screenwriters in Beijing stands at nearly 10,000.

"You'll soon be replaced if you don't concentrate on the writing," Zhao, the Beijin-based scriptwriter, says.

Meanwhile, in the United States, Hollywood screenwriters, grouped under The Writers Guild of America, embarked on a four-month-long strike in November, 2007, which successfully forced producers to raise the their remuneration.

"The Chinese film industry cannot develop without the efforts of writers and their needs need to be met," says Ma Congfeng, vice-president of the Beijing Film Association.