Friends of two Wellington College students who boasted on social media about taking advantage of drunk, unconscious girls say it was just a joke.
School principal Roger Moses said he had contacted Rape Crisis and other agencies to talk to students about the importance of respecting women.
One of the messages posted on the Facebook page said "if you don't take advantage of a drunk girl, you're not a true WC boy."
A Year 13 student, who said he was a close friend of the two boys, said the pair were joking and went too far.
"Probably just at one point the language got out of hand. I definitely wouldn't say it's the usual thing at Wellington College for language like that to be thrown around," he said.
"I do think that probably similar things have been said around the country by different schools in a joking manner, and I do think it's just unlucky that it offended a group of girls that decided to do something about it, and good on them."
He said his friends knew taking advantage of girls was wrong, but they had learned a lesson not to make light of the issue.
"Before this incident it was sort of a hot topic to joke about, and I think this has been a massive learning curve about the whole thing. But the whole time they do realise that there is a strict difference between joking, and what's right and what's wrong. And they both know about what's consent and stuff like that."
Other students at the college had similar views.
"I think it's just a joke that's been blown out of proportion really. Obviously it's not a nice thing to say, but obviously there's no intent in it, he obviously didn't mean it."
Mr Moses said the issue of consent was talked about at an assembly for all Year 11 to 13 boys today.
"It was a pretty emotional affair as you can appreciate, because many of the boys are very angry about what's happened. They don't want to be tagged with this, they feel pretty upset that two of their [peers] have let them down in a pretty bad way."
Mr Moses said at the assembly he talked about the school's key values, one of which is respect.
"I talked to the boys about what respect entails, I spoke about, got them to think about their mums, their sisters, their aunts, their grandmothers, their girlfriends and I talked about the dangers of when we objectify women, and we reduce them to less than people, the huge damage that actually occurs."
Mr Moses said the school was dealing with the boys who put up the postings individually.
Ministry of Education spokesperson Katrina Casey said the Facebook posts were appalling.
"They indicate a casual disregard both for issues of consent and for young women as people, not just sexual objects.
"We've talked to [Mr Moses] and we're satisfied the school is taking this matter very seriously, both in terms of the individual boys, and in looking at whether there are any deeper issues that need to be addressed by the school in terms of understanding of consent and respect for young women."
She said teaching consent was crucial in the education of young people, which was why the ministry revised sexuality education guidelines in 2015.
But Kate Fitzpatrick, an associate professor of education at Auckland University, said they did not go far enough because they were not compulsory.
"The Ministry are pretty hands off with this. They maintain that schools are self-governing, and they haven't put any pressure on schools at all to implement these guidelines, which is problematic."
Richard Aston, the head of mentoring programme Big Buddy, said even if they were compulsory, it was unlikely to change young boys' attitudes.
He says it was fathers and family members, not teachers, who needed to step up and talk to boys about consensual sex.
"It's a call to parents, and particularly the men in those lives, to get involved and start talking to their boys about sexual attraction to girls, how they treat girls, including: 'it's just not OK to have sex with a drunk girl.' And that needs to come from a man, because it's going to be heard better."
The Ministry of Education said it was not aware of any similar investigations at other schools.