Indonesia has announced a sharp rise in its death toll from Sunday's earthquake and sea surges, as information from remote areas becomes available.
The people of Aceh can scarcely come to terms with the disaster
The government now says that 79,940 people died as a result of the quake and the tsunamis it triggered.
Relief workers have finally got to some remote areas on the west coast of Sumatra, near the quake's epicentre.
But many other areas are still out of reach, and there are fears the death toll is likely to rise still further.
After four days without contact, aid workers have finally reached Meulaboh, one of the largest towns on the western coast - and the closest to the earthquake's epicentre.
Arriving by ship, the rescue teams gave out much needed supplies in the town, most of which is thought to have been virtually flattened by Sunday's earthquake and subsequent sea surges.
Emil Agostiono, a spokesman for the Indonesian Ministry of People's Welfare, said he estimated that about 10,000 people had died in Meulaboh alone.
But told the BBC that there were still problems in getting aid to the people in the west coast region, adding that it would take about a month to restore road links.
Helicopters are attempting to fly in relief supplies, but so far they have been unable to land in many areas due to the floods.
There are thought to be only two helicopters available for use in the whole of Aceh, and rescue workers are citing this as a major factor holding up the relief effort.
"There are just simply not enough helicopters to get to the affected areas," admitted Dr Mulya Hasmi, the head of the health department in Aceh.
Even in the more accessible Banda Aceh, the capital of Aceh province on the northern tip of Sumatra, survivors are still desperately short of basics such as clean drinking-water.
A BBC correspondent in the city, Andrew Harding, says the logistics for distributing aid are extremely daunting.
There is only one small airport, petrol is scarce and key coastal roads have been blocked where the tsunamis took out bridges.
Meanwhile, in the region's hospitals, staff have been overwhelmed by the numbers of dead and injured. Infection is already said to be spreading in the tropical heat.
Health experts are warning that - in all the countries affected by Sunday's disaster - outbreaks of diseases such as malaria and cholera could prove as deadly as the effects of the earthquake, unless preventative measures are taken as soon as possible.
But the sheer scale of the disaster is proving too much for local officials to cope with.
"Aceh's health system is not able to cope because Acehnese medical staff are either dead, or too traumatised to work because they have lost family members," Dr Hasmi told the BBC.
Towns on the west coast appear to have been very badly hit
On the streets of Banda Aceh, thousands of Indonesian troops have been drafted in to help clear the rotting bodies.
With little ceremony, rescuers are using bulldozers to dig mass graves and bury the thousands of corpses.
But they are still not working fast enough, and bodies continue to litter the streets, according to our correspondent.
Despite clearing the river of corpses on Wednesday, thousands more had washed into the city with the tide by Thursday morning, he added.
The humanitarian disaster in Aceh is complicated by the continuing separatist conflict in the province.
On Thursday, Indonesian President Susilo Bambang Yudhoyono called on separatist rebels to lay down their arms and help re-build the region.
Both sides declared a ceasefire after Sunday's earthquake, but some rebels have remained active in Aceh despite the devastation.
President Yudhoyono said the hope for Aceh was to build a future with the rest of Indonesia.