China's richest man has praised the long hours expected of workers in high tech companies as a 'huge blessing' for young workers.

Jack Ma, founder of online marketplace Alibaba, defended the company's '996' work schedule - which expects employees to submit to 12-hour shifts between 9am and 9pm during a six-day week.

Of the 168 hours in a week, Alibaba employees are expected to spend at least 72 of them while in work.

China's richest man said his employees were 'lucky' to be working 72 hours a week

Ma was discussing the perceived lack of work-life balance among Chinese high tech workers.

He told employees: 'I personally think that being able to work 996 is a huge blessing,' he said in remarks posted on the company's WeChat account.

'Many companies and many people don't have the opportunity to work 996. If you don't work 996 when you are young, when can you ever work 996?'

The issue has fuelled an online debate and protests on some coding platforms, where workers have swapped examples of excessive overtime demands at some companies.

Ma, a former English teacher who co-founded Alibaba in 1999 and has become one of China's richest people, said he and early employees regularly worked long hours.

'In this world, everyone wants success, wants a nice life, wants to be respected,' Ma said.

'Let me ask everyone, if you don't put out more time and energy than others, how can you achieve the success you want?'

Ma referred to the tech industry today where some people are without jobs, or working at companies in search of revenue or facing closure.

'Compared to them, up to this day, I still feel lucky, I don't regret (working 12 hour days), I would never change this part of me,' he said.

Staff at Alibaba are expected work between 9am and 9pm six days a week. He said the 72-hour week was 'a huge blessing'

This month activists on Microsoft's GitHub, the online code repository site, launched a project titled '996.ICU' where tech workers listed Alibaba among the companies ranked as having some of the worst working conditions.

On Thursday, an opinion piece published in a state newspaper argued that 996 violated China's Labor Law, which stipulates that average work hours cannot exceed 40 hours a week.

'Creating a corporate culture of 'encouraged overtime' will not only not help a business' core competitiveness, it might inhibit and damage a company's ability to innovate,' the unnamed author wrote in the People's Daily.