A brutal schoolyard fight has surfaced on social media showing two pupils at the country's largest college slugging it out so fiercely one boy is left with a head injury.

The sickening encounter was shot last week during an interval at Rangitoto College on Auckland's North Shore.

Today the college's acting principal Don Hastie confirmed the fight took place at the college during school time and involved two pupils.

The fight was immediately referred to the police and the school's board of trustees.

The college was also working with NetSafe and YouTube to have the video removed from social media to protect the privacy of the students involved. 

The disturbing footage shows two pupils trading blows and kicks in a fast-paced fight while scores of girls and boys watch on in a central concrete courtyard.

At one point a blow fells the teenager to the ground.

The bruising encounter lasts around a minute.

It is understood one of the boys suffered a hand injury and the other is nursing a cracked jaw.

A person who contacted the Herald claimed numerous teachers were on duty that day who turned a blind eye to the fight in the centre of the college.

A claim was also made the college did little about bullying and the students were not dealt with correctly.

But Hastie, who was aware of the video, said staff and senior teachers were quickly on the scene and defused the fight immediately.

He said it was disappointing but such fights were far from commonplace and both boys were dealt with swiftly.

"Fighting is not part of our culture and such behaviour is extremely rare," he said. "We view this isolated incident very seriously and as such have taken swift and appropriate action in accordance with policy and Ministry of Education guidelines to bring the individuals involved to account."

He said staff and students were shocked by the behaviour, which was competely foreign to school values.

"We are extremely disappointed that this one-off incident has the potential to damage our excellent reputation - a reputation that is built on respectful relationships among our more than 3200 students in an environment that is extremely safe and one where student well-being is paramount," said Hastie.