The Indonesian government is considering making earthquake and tsunami-devastated areas into mass graves as the death toll from last week's disaster continues to climb.

As search teams pulled more bodies from obliterated neighbourhoods in the city of Palu, the disaster agency said the toll had reached 1,649, with at least 265 people still missing.

More nations sent aid and humanitarian workers fanned out in the countryside, while more black body bags were arranged in a row in the crumpled neighbourhood of Balaroa, destined for a mass grave.

Relatives cried as mourners placed long pieces of white cloth, to represent a Muslim burial rite, inside the bags.

Among them was 39-year-old Rudy Rahman, who said the bodies of his 18 and 16-year-old sons had been found. His youngest son remains missing.

"They were found in front of my brother's house opposite the mosque," Mr Rahman said. "They found them holding each other. These two brothers were hugging each other."

Balaroa was one of the areas hardest hit on September 28 by the magnitude 7.5 quake, which threw homes in the neighbourhood tens of metres and left cars upright or perched on eruptions of concrete and asphalt.

Many children were in the mosque at the time of the quake for Koran recitation. An assistant to the imam had said none survived.

Indonesia's leading security minister, Wiranto, said the government is mulling the possibility of turning Balaroa and Petobo, another neighbourhood in Palu, into mass graves.

Petobo disappeared into the earth as the force of the quake liquefied its soft soil. Liquefaction also struck a large section of Balaroa.

Wiranto said efforts to retrieve bodies are problematic in those neighbourhoods, where homes were sucked into the earth, burying possibly hundreds of victims.

He said it is not safe for heavy equipment to operate there.

Wiranto also said the government is discussing with local and religious authorities and victims' families the possibility of halting the search and turning the areas into mass graves.

The victims can be considered "martyrs", he said.