An 82-year-old man and his 41-year-old son were found living in a forest in central Vietnam after they went missing during the country's war with the United States, an official said.

The older man could communicate a little in the Cor ethnic minority language, but his son only knew a few words, an official at Tay Tra commune in Quang Ngai province said on condition of anonymity.

Ho Van Thanh was last seen running into the woods with his then-infant son Ho Van Lang after a bomb exploded in his home, killing his wife and two other children in 1973, newspaper Dan Tri reported.

They were discovered when two people from a nearby village ventured 40 kilometres into the forest looking for firewood and spotted the two men's treehouse. The villagers reported the find to local authorities who recovered the pair on Wednesday.

The two men survived by cultivating forest vegetables and hunting animals. They had no contact with the outside world, the report said.