Police in Papua New Guinea are hunting for a notorious criminal after violence at a school fete left eight people dead and a severed head hanging from a power pole.

According to local media, an armed gang attacked villagers gathered at the fete in Kainantu district last Friday, and killed four people.

One report said the gang's leader interrupted a speech by a local magistrate, produced a gun and shot him dead.

The villagers retaliated by killing three of the gang members. One was beheaded and the head hung on a power pole.

Another suspected gang member was killed the next day.

The gang's leader, Patrick Sira, is wanted by police over a string of murders, rapes and robberies.

He was able to escape but may have been shot in the leg.

Police have been unavailable for comment.