For the first time, Christchurch Boys' High students will be allowed to grow moustaches to support Movember.

Usually, boys are expected to be clean shaven.

Principal Nic Hill said students can participate in Movember on the proviso the boys can prove they're raising money for the cause.

"They have to be willing to have a deep conversation with me if I bump into them and they have to be groomed they can't just have stubble."

He said the boys are allowed to begin growing their facial hair after prize giving on Thursday.

"There's a good message about men's health, men talking and looking after each other that, you know, really fits what we are about.'"

The school's decision comes a week after Movember New Zealand said that many schools were preventing boys from taking part.

"Mental health and suicide prevention is a big issue amongst that demographic and we think this could be something that is a really proactive way to go around trading conversation and tackling the issue," Robert Dunne of the Foundation said.

Movember begins today, with funds raised going towards issues like prostate cancer to poor mental health.