A teenage student was taken to a barber for a forced haircut by staff at Adelaide's Islamic College, protesters say.

Some of the parents of students at the college staged a protest outside the campus in suburban West Croydon on Thursday morning.

The protesters said school welfare officer Sheikh Hassen Gabress drove the student Mustafa Hassan, aged 14, to a barber last week and ordered the boy's hair be cut, without his mother's knowledge.

"I felt scared, I thought [the school welfare officer] was going to do something bad to me," the teenager said.

"He said to me 'you're too much trouble, you're a bad boy, I'm going to expel you, I'm going to make sure you get expelled'."

Some of the parents who protested outside the school sealed their mouths with tape and held signs saying "Now hair cutting, is flogging next?".

Islamic College of SA student Mustafa Hassan before and after his haircut.

Bayan Mohamed, a spokesman for the boy's parents, said the school had behaved unacceptably.

He said the boy had tried to stop the barber from cutting his hair.

"The boy was fighting them and the hairdresser himself was confused. Was he going to listen to the boy ... or to the guy?" he said.

"[The barber] starts asking 'Who are you? Are you the father or whatever?' so it was out of control.

"To tell the kid off, by the religious co-ordinator, which is scaring them and then going to the principal — and then for the same person to get involved and drag the kid and take him to the barber shop — I don't know, what can I say about this one? It is scary."

The statutory authority that oversees independent schools, the Education and Early Childhood Services Registration and Standards Board of South Australia, has received a formal complaint about the incident.

It said that complaint would be included in a broader investigation into the school.

Mother said she never gave permission

The teenager's mother said her phone had been on silent and she never gave the school permission to take her son for a haircut.

She said her husband was overseas and the school had phoned the boy's adult stepbrother instead.

School welfare officer Sheikh Hassen Gabress drove the boy to the barber. ( ABC News: Candice Marcus )

The mother said the school welfare officer, Sheikh Hassen Gabress, drove her son to a barber at Arndale shopping centre, her son had resisted the haircut and was crying when he got home later.

College principal Zulfiquar Ali said it was school policy to get parental permission before students were taken from the school grounds.

"We do not take the students out of the school without the parents' consent and if we have taken someone out of the school we have taken them out with their parents' consent," he said.

He denied the boy had been taken against his will and said the school obtained permission from his "caregiver" but would not confirm who that was.

"I spoke to the child myself and the child said he was very willing to get the haircut and his mother was not taking him to the barber [as] she was extremely busy," he said.

"I said 'Would you like us to help?' and the child said 'yes'."

Mr Ali denied any suggestion the boy had been threatened with expulsion because of his hair and said he was happy to speak with the student's parents if they wished.

Principal questions other parents' right to protest

He said he was unaware of any complaint to the Education Department.

"If any complaint comes to us we will deal with it. Preferably the parents should have approached me ... if they found something had not followed proper procedures," he said.

Mr Ali said it was wrong of other parents to protest outside the school because it was not their child involved in the matter.

"What right have these people got to ask questions about a specific child if the child's parents are not approaching us?" he said.

South Australian Education Minister Susan Close issued a statement.

"If true, this seems an inappropriate overreaction to what should be a routine matter of upholding a school policy on uniform and appearance," she said.

The Department of Education and Child Development's (DECD) Anne Millard said it was a school responsibility to enforce dress codes.

"The DECD, which sets policy for government schools, does not consider non-compliance with a school's dress code a serious enough offence to deny a student access to learning," she said.

Earlier protests by parents outside the college have alleged financial mismanagement, unfair dismissal of staff and a decline in academic standards.

The schools registration board has been asked to ensure the Australian curriculum is being taught appropriately at the college.