The massacre took place in Enga Province, the ABC broadcaster reported, adding that local authorities are still counting bodies and the death toll could increase to 65.
"This is by far the largest [killing] I've seen in Enga, maybe in all of Highlands as well, in Papua New Guinea," Royal Papua New Guinea Constabulary Acting Superintendent George Kakas was quoted as saying by the broadcaster.
The report added that the massacre involved the same tribes that killed more than 60 people last year.