Relief efforts have started but roads were covered with mud, smashed vehicles and the debris of collapsed buildings and bridges, making travel difficult.
Several navy ships have been dispatched to the coast to contact whole cities and villages as yet unheard from.
In Banda Aceh, where as much as five percent of the 300,000 population is believed dead, residents were stricken with grief and numb with shock.
"I have given up searching for their bodies," said Rohani Amad, 40, wiping her eyes with a black Muslim headscarf, days after two sisters and her 16-year-old daughter disappeared.
The fear of more deadly waves had people on edge.
"The water is coming, the water is coming," shouted terrified survivors as they fled in the latest of a series of false alarms.
But all was not as bleak.
In Banda Aceh, when relief workers removed 183 bodies stored on a mosque floor after the disaster, they found a man still alive whom they suspected had been there the whole time.
"He was sitting there among all the bodies in a corner. He was badly hurt and has been taken to hospital," said the Red Cross's Sy.
The government and foreign donors have begun airlifting food and water into Aceh, some 1,700 km (1,000 miles) northwest of Jakarta, but the challenges are daunting.
"The scale of this disaster is incredible. It is unbelievable," Information Minister Sofyan Djalil told Reuters.
"On Sunday the system simply broke down. The local government was simply paralyzed because many of their families, even they themselves, were victims," he said.
The region was already under civilian emergency rule as part of efforts to quell a separatist insurgency that began in 1976. Rebels have announced a cease-fire as people seek loved ones.
Food and other essentials like fuel were in short supply.
"There is no food here whatsoever...I haven't eaten in two days," said Vaiti Usman in Banda Aceh, gesturing angrily at her filthy sarong and saying it was the last of her possessions
In Meulaboh, communications and regular power sources were not functioning. Military headquarters used a generator for electricity.
Sunday's quake triggered a wall of water up to 10 meters (33 ft) high speeding across the Indian Ocean. There have been numerous aftershocks from the quake, including a strong tremor late on Wednesday.
Across Asia, the death toll neared 77,000 with thousands still missing. <12/29/04>