Police have charged a fifth teacher from Sydney's prestigious Knox Grammar School with child sex offences.

Police said the 66-year-old man was arrested at Port Macquarie today and questioned about the alleged indecent assault of a former student.

The offences were alleged to have occurred while the man was a teacher at the school in 1976 and 1977, police said.

The 66-year-old was charged with two counts of indecency and one count of assault. He will face Port Macquarie Local Court on May 18.



The arrest was made by Strike Force Arika, launched to investigate allegations of sexual abuse of students at the Wahroonga school dating back to the 1970s.