Wellington College's principal believes a disastrous unofficial school ball vindicates a decision to ban balls altogether.

MORE: Wellington College principal Roger Moses: School balls

A number of students are understood to have needed medical attention for excessive drinking at the parent-organised function on Saturday night.

Roger Moses said he'll support any event which enhances the experience of students, but a ball is out of the question.

"At best nothing goes wrong, at worst its a disaster. And it appears that this particular event which was organised it would appear by some boys...there's some parental oversight. This was a disaster."

Mr Moses said the event wasn't supported by the school in any way.

"It seems as if there was a lot of alcohol - what they call 'pre loading' - but quite honestly, we've had nothing to do with the organisation of it."