A chunk of mountain nearly two miles wide collapsed and caused a mudslide that swept away five remote villages and killed at least 76 people, officials and news reports said Thursday.

Relief operations were hampered by heavy rain and the isolation of the site, Morobe Province. It is about 185 miles north of the capital, Port Moresby. Communications with the area are virtually non-existent.John Giheno, the minister for state, said the slide occurred Tuesday morning and swept through Mitsing, Malafan, Zumara and Tari villages in the mountaineous Kaiapit district.

The Australian Associated Press reported a fifth village, Marafau, was destroyed. It quoted one villager as saying the mudslide turned Marafau into a mass graveyard, which "fell away like a sliced piece of meat."

"It was all over in about five minutes," AAP quoted the witness, who was not named, as saying.

A piece of mountain up to 1,500 feet high and two miles wide collapsed into the upper reaches of the valley and released an "unimaginable torrent of earth, rocks and dust," AAP said.

It said the slide appeared triggered by volcanic activity, not heavy rains.

Giheno said one body was recovered and that 615 villagers were accounted for. "At this stage, 75 people are missing, presumed dead," he said.

The villages are about 4,950 feet above sea level. Houses in the area are mainly flimsy traditional grass-thatched structures built on stilts. Villagers exist by raising pigs and farming sweet potatoes.

AAP correspondent Ian Vallance, based in Port Moresby, reached Zumara Thursday and said crude crosses dotted the village.

"Grieving relatives sit alone with their sorrow, dwarfed among the rubble, crying laments for lost parents and wives, husbands, daughters and sons," he said.

AAP quoted Zumara schoolteacher Doris Dema as saying, "First we heard screaming and shouting, but didn't know what was wrong.

"Then we saw this huge cloud of dust, like dark smoke, rising straight up into the air at the top of the valley and there was a sound like a jet plane taking off."