A number of suspensions for drinking, fighting and swearing has led Sydney Academy to ban dances next year. (CBC)

A number of suspensions for drinking, fighting and swearing has led Sydney Academy to ban dances next year.

Principal Kevin Deveaux said a "large number" of students at the Cape Breton high school were suspended after a dance last Thursday, but he wouldn't be specific.

"It was much larger, more than double — well, more than double, almost triple — what we normally see at a dance," he said.

Deveaux said one student from Riverview Rural High School was injured in a fight after the dance.

While the prom this month will proceed, all dances planned for the next school year are off.

Deveaux said the school needs to send a message that bad behaviour is not acceptable.

"It's more the attitude that so many students feel it's OK to drink underage and then come to a school function. It makes the situation unsafe and leads to other problems like fighting and inappropriate behaviours," he said Tuesday.

"It's just at a level that it's not a small problem and it's not something that we can ignore. How can we sponsor an activity where we know that a large number of students are going to display the behaviours that's going to end up requiring us to suspend them? That's unsafe, that's dangerous, it just doesn't make sense."

About 750 students attend Sydney Academy. Up to 30 were suspended, according to media reports.

Deveaux said teen drinking is a bigger problem that it used to be.

'There's many more that weren't caught.'— Principal Kevin Deveaux

"If you caught a large number drinking or under the influence at a dance you know that there's many more that weren't caught," he said.

"It would be really unfair to speculate a percentage, but it's a much bigger problem, I'll say, than it has been in the past."

Deveaux said the suspensions range from three to five days.

He said there were four police officers at the dance. So far, no charges have been laid.