An English teacher in Kunming has been told to apologize for a fine and reward system she imposed on her students and give back money she took, amounting to 50 yuan per wrong answer each teenager made in mid-term exams, reported the Beijing Youth Daily.

Zhao Sha, who worked at Kunming No 10 Middle School, posted an account online on Nov 7 detailing how the fines she levied had totaled 3,950 yuan ($596), the newspaper said.

In addition to the charge for wrong answers, students were required to pay 10 yuan for each point they fell short of a set target. The money taken was used to reward students who made progress and also pay for extracurricular activities.

Some pupils fared better than others. While 12 received rewards, the remaining 28 in the class were fined.

Parents told the newspaper their representative committee at the school had never discussed the scheme. A staff member said the school had not granted permission, and was now investigating.

Han Xiao, a lawyer from Beijing Kangda Law Firm, was quoted by the newspaper saying that there were no legal rights for teachers or schools to fine.

"Parents should have reported the matter promptly to avoid its impact on students' psychological health," Han said.