The NSW Premier was shocked to learn there was an exemption which allows a student to carry a knife on school grounds.
The revelation came after the principal at Glenwood High School sent a letter to parents, following a stabbing at the Sydney school on May 6.
In a letter to parents, dated May 14, Principal Sonja Anderson referenced the NSW Summary Offences Act, which in clause 11C outlines having a knife in a public place or school.
"In addition to having a knife for food preparation, such as hospitality students, the possession of a knife for genuine religious reasons is specified as a reasonable excuse under the act," Ms Anderson wrote in the letter obtained by 2GB.
"However, any knife or implement used as a weapon in a dangerous, violent or threatening way is never acceptable.
"We are currently working with the department and community representatives to discuss how best to enable students to meet aspects of their religious faith and at the same time, ensure our school remains a safe place for students and staff."
NSW Premier says students should never carry knives
At a press conference on Monday, NSW Premier Gladys Berejiklian was pressed on what she thought of the principal's response.
"I was quite taken aback to learn that students can take knives to school," Ms Berejiklian said.
"Students shouldn't be allowed to take knives to school under any circumstances.
"And I think it doesn't pass the common sense test to have students taking weapons of any description to school, even if they're not using those weapons others might, you know, take them from them."
The premier said she would be speaking with the Education Minister about it and reiterated her "strong view" that students should not be permitted to take weapons to school "full stop".
According to the ABC, Education Minister Sarah Mitchell said she and the Attorney-General have discussed the issue.
The NSW Act permitting knives at school
The NSW Summary Offences Act says a person must not have custody of a knife in a public place or school without reasonable excuse, proof of which lies on the person.
There are several "reasonable" excuses for a person to carry a knife, including "genuine religious purposes".
The incident at Glenwood High School occurred on Thursday, May 6.
A 16-year-old boy was rushed to hospital with stab wounds to the stomach following an argument in the schoolyard, AAP reported.
In her letter to parents, Ms Anderson said she had recently visited the 16-year-old and said he was "progressing well".
Counselling support was offered to all students and staff following the incident.
"There is no doubt recent events have been difficult and stressful for everyone — students, staff and families," Ms Anderson said.
"I have been so impressed by how we have pulled together as a community to ensure that our wonderfull school and students are at the forefront of all our decisions."
Do you have a story tip? Email: firstname.lastname@example.org