Women of all ages in Onehunga are going to self-defence classes in droves, as Auckland police hunt a teenage serial sexual attacker.

Police say he's thought to be aged between 12 and 16, and is believed to have assaulted 11 women since October last year - grabbing them from behind and then running away.

The latest attack was on Easter Sunday.

Onehunga Business Association's Amanda Kinzett told Larry Williams people have started avoiding the areas where the man's known to have attacked.

She said the community needs to take control, and with the approval of the local Constable, have enlisted the help of a self-defence teacher.

"He's taken two workshops for us so far, that's 84 women of all age groups, from teenegaers through to senior [citizens], who have taken those classes, and I've got another 100 women on a waiting list."

LISTEN ABOVE: Onehunga Business Association's Amanda Kinzett speaks to Larry Williams

Police have been door knocking, have given out hundreds of flyers, and have released a phone number for the public to call if they have information about the attacker.

Detective Constable Patrick Whitiora said they just want this young man off the streets, and given the help he needs.

"This young man may have told someone about what he's been doing, he needs help and he needs to be stopped.

"Everyone has the right to walk our streets without being scared, and there's no place for this kind of behaviour in our communities."

Detective Constable Whitiora asks if he's your mate, your brother, or son - please contact police, and let them help him.