A Mandurah teacher has been left red-faced and could be facing disciplinary action after "extremely graphic" nude pictures of her were reportedly made public by students and shared on social media.

A John Tonkin College teacher is understood to have lent a thumb drive to a student, warning them not to click on photos filed on the USB stick.

The John Tonkin College teacher is understood to have lent a thumb drive to a student which contained the photos. Credit:Mandurah Mail

Curiosity appears to have got the better of the student, who not only clicked on the photos, but has reportedly shared them with friends, who then shared them with the world via social media.

The photos were reportedly "extremely graphic" and showed the teacher naked with her boyfriend.

A source at the school told the Mandurah Mail "a few people are in trouble" over the photos, with students being quizzed by staff.

The Education Department said the matter had been referred to its "staff standards and integrity team" and would be "fully investigated".