"Most of the hospitals are functioning, but are overloaded. There is a lack of space in the hospitals," said Charlie Higgins, the UN's humanitarian coordinator in Yogyakarta, the main city in the quake zone.

"It's getting out the basic medical supplies to the hospitals that is important," he told AFP.

Foreign rescue teams from China, the United States, Qatar, and Singapore among others have set up field hospitals and lent a hand to help overworked staff at area hospitals.

Higgins said most of those who needed life-saving emergency treatment had been cared for and that aid agencies were now concerned about the long term.

"They are trying to move people out from the wards and beds to their homes. But for some, the homes are ruined," he said. "So that is a problem."

More than 139,000 homes were destroyed or damaged in the quake, according to the social affairs ministry.

At the bustling Bantul General Hospital, the co-ordinating doctor, Hidayat, said the facility was treating about 50 patients, some of whom were lying on cots in the entrance.

"That's because they don't have a house to go home to," Hidayat said.

Sumartini, 33, lay on her side with her right leg in a temporary splint made of cardboard. She had been there since Saturday without surgery.

"I'm waiting for a doctor from Singapore," said Sumartini, whose husband was also at the hospital with eye and leg injuries.

Rescue teams were still looking for bodies under the rubble.

Six Spanish rescuers aided by sniffer dogs combed through the rubble of a village market in hard-hit Bantul district, looking for bodies or even possible survivors, the Detikcom online news service said.

Local traders were quoted by Detikcom as saying there were many people in the market when it collapsed and that some might have been trapped inside.

Amid complaints from residents that aid has been too slow to arrive, Indonesian officials have defended the relief effort while the UN's Higgins offered a relatively upbeat assessment of the situation.

"On the whole, there are enough resources to deal with the emergency," he said.

Wet weather in recent days and clogged roads have hampered distribution of needed supplies by trucks and some survivors have were bracing for a sixth night without shelter.

Military and rescue helicopters are delivering badly-needed food to isolated areas, and transporting the injured to hospital.

But hundreds of survivors converged on the governor's complex in Yogyakarta hoping to pick up extra rations for their devastated villages.

Villagers sat around a large pavilion where sacks of rice and parcels of instant noodles were being distributed.

"We need everything. Our village is the most destroyed in the area, so we want anything we can get," said Wakidgian, 42, from the flattened mountainous village of Dlingo in Bantul.

"We come from an isolated area close to the mountains, so not much help has reached us," said another survivor, Mardain, 32, who had waited for hours for his number to be called.

Meanwhile an Indonesian minister encouraged survivors to migrate to other islands in the sprawling archipelago nation, a report said.

"We have notified district chiefs to make lists of people who are interested in moving from earthquake-prone areas," Manpower and Transmigration Minister Erman Suparno was quoted as saying by Detikcom.

"The information we have is that the lava is flowing. The crater is full of lava. We don't know which direction it will flow," Colonel Ismael Daho, head of the emergency management team for the Comoros archipelago, told Reuters. He said the lava was covering an area about 3 km square (1.2 miles).

Residents were nervous, but the volcano's periodic past eruptions, which have rarely have caused a major disaster, have tempered some on the island of 300,000 against panicking.

"Everyone is scared. No one could sleep the whole night," Jimmy Mohamed, from the village of Nvouni on Karthala's western slope, told Reuters. "But we all stayed and no one left. We're used to this."

Until the observation flights - flown by African Union troops still on the island after monitoring the May 14 presidential election - determine where the lava might flow, authorities urged people to wait for evacuation instructions.

The lush green slopes of Karthala, covered with vanilla and ylang ylang plantations, form most of the largest island of the three in the Comoros chain, 300 km (190 miles) off the coast of east Africa.

Karthala has rarely punished Grande Comore harshly. The worst disaster on record came in 1903 when 17 died from noxious fumes that seeped from cracks.

The last big eruption, in April 2005, sent thousands fleeing in fear of poisonous gas and lava. That was the first eruption in more than a decade, but the volcano has erupted on average every 11 years over the past two centuries.

In November, Mount Karthala fired clouds of ash and sparks across the island, blanketing the capital Moroni and other villages in grey dust. Moroni is about 15 km from Karthala's crater.