A teenage boy has been jailed for 11 years for what police called a random act of fatal violence which left another teenager dead.

Petani Fa'avae, 16 at the time, was found guilty of murder earlier this year after 14-year-old Manaola Kaumeafaiva was stabbed to death outside Avondale College during a church dance in Auckland in October, 2006.

In April a jury in the High Court at Auckland took just over five hours to find Fa'avae guilty of murder, one charge of wounding with intent to cause grievous bodily harm, and two charges of assault with a weapon. Fa'avae was acquitted on one charge of assault with a weapon.

During the incident another teenager was stabbed in the arm.

After the incident police said there was no provocation and the victim died within minutes of being stabbed.