A New South Wales high school student says she felt "disgraced" after her principal lectured female pupils on coloured bras and short skirts, following remarks about sexual harassment and violence.

Several female students of Engadine High School have told the ABC that Kerrie Jones referred to the uniform policy breaches as a distraction to males, during an assembly on Thursday.

The ABC has been unable to confirm with Ms Jones or the NSW Department of Education that this remark was made.

In an email since sent to parents, Ms Jones said she began by acknowledging the "tremendous work done by people across the world in recent times to stand up and speak out about sexual harassment and violence".

"I then went on to speak about our school identity and how we wear our uniform with pride," she said.

"I did refer to the length of some girls' skirts and the practise of rolling the top to shorten the skirt as being not in line with school's uniform policy."

But the principal said the girls were connecting the two subjects.

"Upon reflection it is regrettable that I didn't sufficiently and clearly separate the two points which may have led to some girls connecting the two," the email reads.

"For this I am truly sorry as this could not be further from my beliefs."

Student felt 'disgraced'

A student who was at the all girls assembly has told the ABC she and other students believed there was a clear link between the principal's talk on sexual harassment and how they wore their uniforms.

The student, who asked that her identity not be revealed for fear of being suspended, said she did not accept the principal's explanation.

"Every girl was called out of class down to the quad to talk and our principal Ms Jones was saying about how our skirts were too short and how our bras through our shirts were noticeable, and that was distracting males," said the student.

"I was disgraced, I was embarrassed that my school would even think of saying these sort of things to girls."

"This is a place where I am supposed to feel safe and comfortable but I honestly don't after what she said."

The mother of another female student told the ABC she was "horrified" when her distraught daughter phoned her immediately after the assembly.

"There was only one way that the girls could have taken that," said the parent, who asked that her name not be revealed to protect her daughter's identity.

"[To say] they are asking for trouble dressing the way they do, I mean in this day and age, that is pretty archaic."

"I find it very unusual that a whole assembly from years 7 to 12 could all take it the wrong way."

The parent said a number of girls at the school, including her daughter, roll their skirts at the waist due to the shape and sizing.

"But the bra thing, I know a lot of the girls rebelled and wore coloured bras the very next day just to stand up for themselves and to make a point," she said.

Department defends Ms Jones

In a statement the NSW Department of Education defended Ms Jones and said the two matters raised by her were separate.

"The principal has acknowledged and apologised for any misunderstanding that these issues were spoken about together at the same time."

"It was not her intention and a note has been sent to parents to apologise."

The department would not say if it was investigating complaints or taking any further action.

The ABC has requested an interview with Ms Jones via the department.