Providing emergency healthcare is also challenging, according to the UN Office for the Coordination of Humanitarian Affairs (OCHA), which said that around 2,500 people have been seriously injured in the disaster.
"Most of the victims were found in Palu and they were hit by tsunami, particularly in the coastal areas near Talise beach", the spokesman said. Numerous missing are believed to be dead as rescue efforts enter its second and final week.
Officials fear at least 5,000 people may still be missing in Indonesia following a deadly natural disaster and tsunami that killed 1,763 people and devastated the northern island of Sulawesi.
He said that a further 5,000 people were suspected to be missing in the Palu subdistricts of Balaroa and Petobo but that officials were still looking to verify the claims. They are all missing.
But the biggest killer was probably soil liquefaction, which happens when a powerful quake turns the ground into a liquid mire and which obliterated several Palu neighbourhoods.
Nugroho said other victims still are buried in the mud and debris and have not yet been recovered. The United Nations has said some 200,000 people, including tens of thousands of children, are in need of help. "We don't want this".
Mr Nugroho said the debris would be removed from those places before they would be turned into public spaces like parks and sports venues.
"I am coming to Palu to report that we need tents, because 95 % of our village has been destroyed", said Simsom Mudju from Lindu, who clambered aboard the chopper to tell the outside world about his marooned community's plight.
Eight victims in black body bags of the national search and rescue agency were arranged in a row in the crumpled Palu neighborhood of Balaroa, destined for a mass grave. The natural disaster ripped apart the roads, hindering access, so helicopters have been dropping aid supplies to more remote areas.
Dede Diman told Reuters that rescuers had not even begun to search the area where he believed his sister was.
"We're already angry", said Diman, who is living in a shelter with his brother and another sister.
Nugroho confirmed that rescuers found the body of the South Korean, making him the only foreigner known to have perished in the disaster. "They erupted in cheers and gave a thumbs-up sign before we took off". "We're only collecting data to find out how many students are safe". The team's task is to find and retrieve the bodies at the surface to clear the way for the heavy machinery to come in and dig deeper.
"One of the only things I have dared to save was my Bible", she said, holding the well-thumbed copy in her lap.
"What's the point anyway?"
The school had lost at least seven students and one teacher, he said.
"It is not uncommon but when it hits, it hits hard". With nearly no effort he unearths the body of a long-haired lady buried in mud.
Two days after the earthquakes and tsunami hit the region on September 28, forcing the closure of the airport, light aircraft could use part of the facility with top priority given to aid relief and evacuation work. The archipelago sees frequent earthquakes and occasional tsunami.