No charges against Knox teacher

The child sex abuse royal commission has apologised for mentioning the name of a teacher who was alleged to have had a two-year affair with a Knox Grammar boy.

It says it will not be recommending any charges against the teacher, who has now been given the pseudonym ARZ.

David Lloyd, counsel assisting the commission, said he made an error in mentioning the teacher's name when questioning witnesses about the allegation made by a former student who was threatening to sue the elite north shore Sydney school.

"The error is as counsel assisting entirely mine and I apologise for it," Mr Lloyd said.

"The commission is not pursuing it for reasons which include that the student mentioned is now dead."