Over 670 people now feared dead following landslide in Papua New Guinea's highlands

A United Nations agency has confirmed more than 670 people are presumed dead following a landslide in Papua New Guinea's highlands on Friday, Report informs via ABC.

The International Organization for Migration's chief of mission in Papua New Guinea, Serhan Aktoprak, said the scale of the impact was much greater than initially thought.

"Now, the estimates suggest that 150 plus houses may be under the debris of six to eight metres deep. And they are fearing that approximately 670 plus people could have lost their lives," Mr Aktoprak told the ABC.

He said terrain surrounding the disaster zone in Enga province remained dangerous and unstable – prompting the evacuation of about 1,250 survivors.

"When I was speaking with my colleagues … about an hour ago, as a matter of fact, they had to run away from the site because of the increased danger as rocks nonstop keep falling and the land continues to slide," Mr Aktoprak.

"This coupled with the heavy bulk of soil that had already landed earlier, is putting pressure on the surrounding houses, hence the evacuation of those."

The UN, government agencies, police and military personnel are assisting with the recovery.

Locals were digging with shovels, sticks and bare hands to find people they fear are buried beneath rubble and rock.

Locals used sticks, hands and shovels to dig out bodies trapped under the landslide. (Supplied: Steven Yange)

It is estimated that around 150 houses were covered by the landslide.

By Sunday, only five bodies and a leg of a sixth victim had been recovered.

Homes and two health centres lie underneath where the side of the mountain gave way on Friday.