A youth has been axed to death and three others are nursing knife wounds after an attack on a Port Moresby settlement following the earlier rape of three women.
One woman from the settlement is missing.
Police appealed for her return and for calm, fearing the matter could boil over into an ethnic conflict between Goilala people from Central Province and Highlanders.
The raped women were all Highlanders living in Port Moresby.
The dead, injured and missing are all from a settlement of Goilala people.
Police say the youth died from wound inflicted during a revenge raid on the Goilala settlement, believed to be by relatives of the raped women.