A teacher who forcibly gave a high school student an ugly haircut in Si Sa Ket has apologised after being reprimanded, according to the local education office.

Chuchart Kaewnok, director of Secondary Educational Service Area Office 28, did not disclose the teacher's name but he said the incident took place at Yang Chum Noi Phitthayakhom School in Yang Chum Noi district on July 3.

Mr Chuchart said the student's mother, identified as Jin, 33, owner of a restaurant, took to Facebook to expose the incident involving her daughter.

She said the teacher deemed the student's hair was too long and cut off one side, leaving an "ugly" haircut as punishment.

The incident occurred in the school's courtyard in the presence of other students who were lining up for the morning assembly. The punishment caused shame and mental anguish as a result, according to Ms Jin.

Mr Chuchart said he spoke to the girl's mother to settle the issue during a meeting also attended by Democrat Party MP Issara Seriwatthanawut, district chief Suporn Theerarojchalee and the director of Yang Chum Noi Phitthayakhom.

Mr Chuchart said the Education Ministry has allowed female students to have long hair as long as it is tied in an orderly fashion.

He said the teacher had overstepped his authority, noting he has since accepted responsibility and apologised to the student and her mother.

The teacher has been reprimanded and told not to repeat the act, Mr Chuchart said, adding teachers should be tactful and gentle in handling such issues.

Ms Jin said whether her daughter remains at the school will depend on how well she copes with the trauma resulting from the incident.