The video captures part of this exchange.
"What I'm saying is you know you're not allowed to say the n-word. Even if you're trying to project the idea that the book is about racism, you're not supposed to say it".
The students makes the point that he would be sanctioned for swearing at school and the teacher replies that the context is important.
"You shouldn't be saying it at all, especially when it comes to a white person, it's worse," he replies.
The teacher counters by arguing that she allows students to swear in their speeches.
"That's not my problem. All I'm saying is don't say the n-word. You know you're not supposed to say it. Why are you saying it? Don't say it."
The student also claims the teacher eventually apologised.
"With everything going on I want everyone watching this to repost this".
Responding to Herald enquiries, Lynfield College released a statement to say: "The school is currently working with representatives from the student body, staff and the community in responding to and learning from this incident."
Foon told the Herald that the word should be "deleted from our school book, school plays, you can't even use the f-word in New Zealand without having a beep".
He said that teachers using material that contained the word had no need to use the word itself to teach that its use was inappropriate or to reflect its prior use as a weapon of racism.
He said the student needed to be congratulated for standing up to the teacher.
"Well done, congratulations, you are a brave person to stand up, to call out the teacher for saying the n-word," he said.
"That's what we encourage, to call people out, to be upstanders," he added.
Addressing the student, Foon said: "Thank you for being brave and thank you for holding your ground on what is not right in today's society".
He also encouraged the student to make a formal complaint to the Human Rights Commission.
He revealed he would be contacting the Ministry of Education to recommend a standard be applied across the sector, similar to codes that cover broadcasting.
He said that certain words "have gone past their best-by date" and are "not appropriate in today's context".