SYDNEY - The Papua New Guinea government ordered thousands of residents to evacuate from the path of a still-active landslide on Tuesday, after parts of a mountain collapsed, burying at least 2,000 people according to the government's estimates.

Officials said the odds of finding survivors were slim, even as relief teams have trickled into the difficult-to-access northern Enga region of the Pacific nation since Friday.

Heavy equipment and aid have been slow to arrive because of the treacherous terrain and tribal unrest in the remote area, forcing the military to escort convoys of relief teams.

Heavy equipment and aid have been slow to arrive because of the treacherous terrain and tribal unrest in the remote area, forcing the military to escort convoys of relief teams

Residents have been using shovels and their bare hands to search for survivors.

"The landslide area is very unstable. When we're up there, we're regularly hearing big explosions where the mountain is, there are still rocks and debris coming down," Enga province disaster committee chairperson Sandis Tsaka told Reuters.

Military personnel had set up checkpoints and were helping move residents to evacuation centres, he said.

The United Nations said on Tuesday six bodies had been recovered so far and the total affected population, including those needing possible evacuation and relocation, was estimated at 7,849.

Papua New Guinea regularly experiences landslides and natural disasters that rarely make headlines, but this is one of the most devastating ones it's seen in recent years.

The government has estimated that more than 2,000 people were buried in the landslide which occurred early Friday, sharply higher than UN's figure of 670 possible deaths, and some local officials' much lower estimates.

The government has estimated that more than 2,000 people were buried in the landslide which occurred early Friday, sharply higher than UN's figure of 670 possible deaths, and some local officials' much lower estimates

'Complicated' relief effort

The relief operation was extraordinarily complicated, said Nicholas Booth, resident representative at the United Nations Development Programme (UNDP), with the terrain continuing to move.

"It means that now, the area that's been affected by the landslide is greater than it was at the beginning. We don't know how it will develop, but that's the nature of the geology in PNG," he said.

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A long-running tribal conflict has made it harder for aid workers to access the site, Booth said. Eight people were killed and 30 houses torched in fighting on Saturday.

A total of 150 structures were estimated to have been buried by the landslide.

The UN said on Tuesday that immediate needs included clean water, food, clothing, shelter items, kitchen utensils, medicine and hygiene kits and psychosocial support.

Provincial authorities have requested the international community to send engineers to carry out a geohazard assessment, the UN said in a statement

Provincial authorities have requested the international community to send engineers to carry out a geohazard assessment, the UN said in a statement.

The differing fatality estimates reflect the difficulty in getting an accurate population count. The nation's last credible census was in 2000 and a 2022 voter roll doesn't include those under 18.

READ MORE: Hundreds feared dead after landslide hits remote PNG village

Such estimates should be treated with "great caution", Booth said.

"Most people remain trapped under that rubble and it's just not possible at this stage to make a very scientific, verified estimate," he said. "But it's going to be a very high number of casualties. We have to be prepared for that."