WELLINGTON, March 9 - St Patrick's College Silverstream Rector Gerard Tully said they had been dealing with a "most distressing incident of sexual harassment" involving the four Year 9 boys.

"The students involved have been suspended from school, pending a hearing with the Board of Trustees Discipline Sub-Committee," he said in a statement.

Prime Minister Bill English, a former student of the school, said he was concerned about the reports but said the college looked to be moving to deal responsibly with the matter.

"There's always an element with people in their early teens doing things that show bad judgement ... but I think it's really important that those young people get a clear message that that kind of behaviour is unacceptable," he said.

"The school's making their stance clear. That's the right thing to do and I hope those young people learn a lesson from it, that it's unacceptable."

The suspensions come days after complaints that students at Wellington College had allegedly made inappropriate rape comments on a private Facebook page.

The school held a special assembly on Wednesday to address the posts, which reportedly include "If you don't take advantage of a drunk girl, you're not a true Wc (Wellington College) boy".

Another said "F*** women", according to screenshots.