Sixteen film and television companies issued a joint statement on Tuesday in Hengdian, Zhejiang Province, claiming they would not hire any stars involved in prostitution, gambling or drug abuse for their shows.

"We hold a zero-tolerance policy toward those who are involved in such misconduct and expect all stars and fellow workers in the business to be self-disciplined and strictly abide by the law," read the statement.

The move came after the detention of Jaycee Chan, son of Hong Kong kung fu star Jackie Chan, along with Taiwanese actor Ko Chen-tung last week in Beijing for using marijuana.

All 16 companies, including Hengdian World Studios and Century Great Dragon, are located in Jiangsu and Zhejiang provinces.

A spokesperson of the Hengdian World Studios on Tuesday confirmed the joint statement and reiterated that all celebrities should obey the law like ordinary people.

On August 13, the Beijing Trade Association for Performances and 42 Beijing performing-arts organizations signed an anti-drug commitment, promising not to hire any celebrities who used drugs for shows, reported the Beijing Evening News.

"The impact of the statement is limited for big-name stars who have a large number of fans and markets to make profits," Ying Xiaoqiang, a Hangzhou-based media observer, told the Global Times.

Ying suggested the authorities issue a regulation that forbids stars involved in drug abuse from participating in any entertainment activities within a certain period, like five years, and also ban the broadcasting of their programs or films.

However, some questioned whether the statement violated the spirit of the Anti-drug Law, which stipulates that cleared drug abusers should not be discriminated against in employment.

"It is not discrimination because the stars, as public figures, have strong social influence, especially on their die-hard fans with weak discernment who might imitate the misconduct," said a lawyer surnamed Yan from the Hebei Jigang Law Firm.

Yan added that the companies usually sign a contract of service with the stars and have the right to refuse to hire them.

A number of stars have been detained in recent months for using drugs, including famous screenwriter Chen Wanning who was known by his pen name Ning Caishen, Hong Kong actor Roy Cheung and mainland actor Gao Hu.