The death toll rose to 6,234 while the number of those hurt in the quake more than doubled to some 46,000, with more than 33,000 suffering serious injuries, the social affairs ministry said.

Hospitals in the quake zone were still overwhelmed five days after Saturday's 6.3-magnitude temblor rocked Central Java, with patients spilling out from wards and badly in need of care, a UN official said.

"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, Qatar, Singapore, and the United States 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.

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.