Canberra: A 17-year-old student in Australia was penalised 20 percent marks in his chemistry examination for having a haircut that breached the school's uniform policy, media reported Wednesday.

Dominic, 17, was stopped before entering for the examination at All Saints Catholic Senior College in Casula in New South Wales for sporting a stubble and having an undercut hair style, the Sydney Morning Herald reported.

"I felt like the teacher was trying to make an example out of me," Dominic said. "Some people have worse haircuts than I do."

After struggling in chemistry throughout the year, Dominic put in hours of study to lift his grades and impress his parents.

The family spent hundreds of dollars on his tutoring, the report said.

"I wanted to show my parents and prove to myself I've improved," he said.

Although the new style raised some eyebrows, his mother says the school should have let Dominic sit for the exam and reprimand him later.

The student, instead, returned to school Wednesday to sit for the exam, but with a penalty.

"I don't think they should bend the rules because he's my son, but I don't agree with the way they handled it. That's going to impact his self esteem and academics," Dominic's mother said.

School principal David Fetterplace said the uniform policy has always been made clear to students and the penalty was applied because Dominic was sitting the exam a day late.

"We didn't say you're banned from doing the exam, we said pop off and go down the road, fix your hair and sit the exam when you come back," Fetterplace said.