Activists are calling for more supervision over labor exploitation in an online crusade spearheaded by software developers against the so-called 996 work schedule, which is widely practiced in China's tech industry.

The rules-which require employees to work from 9 a.m. to 9 p.m., six days a week without overtime pay-came under fire after a programmer created 996.ICU, a page on code-sharing platform GitHub.com. The page garnered immediate attention at home and abroad.

The name 996.ICU refers to a saying among Chinese developers that following the 996 schedule puts you at risk of ending up in an intensive care unit.

In the weeks that followed the creation of 996.ICU in March, the page has accrued almost 200,000 stars-which indicates popularity among users.

Users listed tech companies that use the 996 schedule, and then created a licensing agreement that would ban such companies from using their codes.

The 996.ICU page was soon blocked on multiple platforms including the messaging tool WeChat and the UC Browser.

The 996 schedule was allegedly first adopted in 2016 by 58.com, a major online classified advertisement site.

Jiang Ying, a professor at China University of Labor Relations and a leading expert on China's Labor Law, said the rare protest by sleep-deprived tech firm employees underscored the difficulties facing workers who defend their rights.

"When resorting to the legal system for protection, there is a price to pay: time, money and the risk of losing your job. And as a result they took to cyberspace," she said.

Employers are obliged to provide overtime pay, bonuses and welfare benefits to employees working overtime. But many tech company employees said it was too much to hope for.

A senior developer with the e-commerce giant Alibaba, who asked not to be named to protect his career, said employers seldom say the schedule is compulsory, but failure to follow the rules could lead to low performance scores and layoffs.

"Defiant behavior can also lead to losing your annual bonus, which is a lot of money," he said.

To better protect workers from harsh treatment, Jiang suggested that oversight should be beefed up, and systems for lodging complaints should be improved.

China's Labor Law prescribes that the working hours of an employee should not exceed an average of eight hours daily, or 44 hours a week.

Employers may extend working hours after consultation with an employee, but shall not exceed three hours a day or 36 hours a month.

The 996 work schedule, however, can easily ratchet up weekly work to 60 hours.

Jiang said tech firms represent the country's most advanced productive force and should have the wisdom to adopt a more effective way to improve productivity.

Zhao Wei, an industrial sociology professor at Beijing Normal University, said the new industries led by internet companies have revolutionized how workloads are calculated, thus dimming the distinction of working overtime.

"Labor laws should be revised with new industries in mind-which in today's case is the information industry," she said.