China has drawn red lines for vocational school students' internships to prevent them from being forced into doing repetitive and intensive unpaid labor.

To help students learn practical skills, vocational school students are required to work as interns for six months.

However, some avaricious vocational schools have arranged for their students to work as assembly line workers in factories with long hours and many night shifts, the head of the Ministry of Education's vocational and adult education department said in a statement on Friday.

Some forced students to do internships at designated companies, charged students for internships and required students to do internships that were not related to their major, the official said.

The ministry and eight other government departments issued a guideline recently to close loopholes in vocational students' internship arrangements and better protect their rights and interests.

Vocational schools, companies and students should sign internship agreements and no third-party agencies are allowed to organize or manage students' internships or profit from them, the guideline said.

The internships should be related to students' majors and should not be repetitive, labor-intensive or profit-driven, it said.

All school-organized internships should be approved by students and their guardians, and those who do not want to participate in such internships should be allowed to find appropriate posts themselves, the guideline said.

Schools should not force students to take internships at designated companies, or hold their student cards or ID cards as a form of coercion, it said.

The payment for internships should not be lower than 80 percent of that earned by employees in the same posts or the minimum wage, and it should be monetary payment, not vouchers or other goods, it added.

There have been cases of students getting injured while working as interns or committing suicide due to grueling conditions.

A 17-year-old vocational school student jumped to his death from a factory dormitory in July after being forced to work long hours as part of a mandatory internship.

The student, surnamed Yu, was studying computer science at Shiyan Hanjiang Technical School in Hubei province, but the school sent him and more than 90 other students to a factory in Shenzhen, Guangdong province, China Newsweek reported.

They were asked to work more than 10 hours every day carrying boxes that each weighed over 20 kilograms. The students were not allowed to ask for leave or not show up for work, the magazine cited Yu's father as saying.

The father said Yu often complained about the long hours and said he was targeted by his supervisors.

A 19-year-old student at a vocational school in Linwu county, Hunan province, had to have two fingers amputated after his right hand was caught in a machine during a school-organized internship at a new-energy company in January last year, Workers' Daily reported.

As the student had not signed a labor contract with the company, the injury could not be treated as a work-related injury, and the school and the company shirked their responsibilities, the newspaper said.

Ma Jian, director of the department of enrollment and employment at Guangzhou Pharmaceutical Vocational School, said the key to preventing such incidents is for vocational schools to conduct vigorous background checks on companies where their students do internships.

"Internships are not employment, so vocational schools must still follow up on students' conditions and companies cannot hold them to the same standards as full-time employees," he said.

It is unrealistic to expect students under the age of 20 to have great self-discipline, so teachers should contact students every day to learn about their conditions and students should return to school at least once a month to report on their progress, Ma said.

Dong Xiaohui, a 17-year-old student at Jinan Technology School in Shandong province, said the guideline offers assurance to students working as interns that they will not have to worry about getting poor treatment and will be able to learn practical skills.

He worked at a local supermarket chain for more than four months as part of the school-organized internship, where he was paid more than 3,000 yuan ($474) a month and worked eight hours a day with a two-day break each week.