Headmaster Richard Sidorko issued a statement on Monday morning condemning the behaviour of the students over the weekend, and said the school in no way condoned the "walk back" event.

“The so called ‘walk back’ is not a college event; it has never been supported by the college and is in fact strongly discouraged by the college. It is unsafe and dangerous. It is an inappropriate means of showing school pride. There is nothing to be proud of in anti-social behaviour,” he said.

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Graduating Marist students have an annual tradition of walking from Civic back to the college campus in Pearce.

Police received multiple calls about a group of about 120 students about 2am, and were forced to dispatch a team of officers to keep an eye on them.

The students were allegedly walking and running drunkenly on to State Circle, attempting to stop cars. Police say some of the students became aggressive and began abusing officers on the scene. According to ACT Policing, some students also threw rocks at police cars.

It is understood that only a minority of the group were involved in aggression towards police. One Marist student took to social media to dispute ACT Policing’s version of events, saying it had been empty water bottles thrown at the cars, not rocks.

Officers say they were forced to block traffic on numerous occasions along Adelaide Avenue and Melrose Drive to protect the safety of the students. Three of the students were arrested for breaching the peace, although they were later released.

The walk has occurred in previous years without police revealing any major trouble.

This year the march happened after the Year 12 graduation dinner on Saturday night, but Mr Sidorko said students had been told by the school not to do it.

“The college position is that there be no ‘walk back’ and this position is explained in writing to parents and boys before graduation,” he said.

ACT Policing acting Superintendent Jo Cameron said the officers had simply been trying to minimise disruption to traffic and stop the students from being injured on Sunday night.

"As we pointed out in our recent stand up on school formals, police are not against students having a good time, but if things get out of hand action will be taken," Acting Superintendent Cameron said.

"We encourage everyone to go out and have a good time, but police, along with the community, will in no way tolerate antisocial behaviour that could put themselves and other lives at risk."

Mr Sidorko said he was disappointed a small minority had tarnished the reputation of an otherwise “excellent” Year 12 cohort.

“Over 11,000 hours of community service has been done by this year group and that is a better reflection of the true qualities of this group,” he said.

“On behalf of the college I want to apologise to both the police who had to deal with these boys and to the people of the community who were affected by their anti-social behaviour. I appreciate the efforts by the police on Saturday night and regret that they were confronted with this situation.”

with Hamish Boland-Rudder