Police in a remote part of Papua New Guinea are warning men to be on the lookout after a group of knife-wielding women allegedly raped a teenage boy.

The 17-year-old victim had just left his high school in Mendi in the Southern Highlands last Friday when he was confronted by a group of women armed with knives.

The National newspaper reports there were at least 10 assailants and they forced the teenager to lie down and took turns to rape him.

Four women sexually assaulted the youth before passersby disturbed them.

Superintendent Teddy Tei said police are investigating but so far there have been no arrests.

He said it is highly unusual for a male to be the victim of sexual assault in PNG and he is warning men in the area to be careful.

Superintendent Tei feared the women could have infected the teenager with HIV or AIDS.