Boys at an elementary school in south China's Guangzhou City were forced to apply first before going to the toilet even during breaks as a punishment for failing to follow a dress code, according to Guangzhou Daily.

The rule has been enforced since Dec. 12 for a class of third graders in Shuiyinlu Elementary School in Guangdong Province. In the 10-minute break, children have been required by the head teacher Liu to sit on their seats and make an application if they want to answer the call of nature.

Reports say Liu made the requirement after the class lost a collective honor because several boys forgot to wear red scarfs.

The harsh requirement has lead to discomfort among some pupils.

Parents said some boys now suffer from urinary problems. One child had to relieve himself in the classroom, bringing him shame and causing him to return home in tears.

Teacher Liu is strict with students, according to parents, ordering students as well as parents to make written apologies for poor performances in a subject.

Several parents once wrote a joint letter demanding another head teacher when the students were first graders, accusing her of lacking compassion and pursuing fame through improper means.

But the teacher said she has more than 20 years of teaching experience and parents have no right to decide whether her methods are good or bad.

She refused to give an explaination when a reporter tried to reach her.

Education authorities in Guangzhou's Yuexiu District said they had started an investigation.