As many as 5,000 people are believed missing from two hard-hit areas in Palu more than a week after the Indonesian city was devastated by an earthquake and tsunami, an official said Sunday.

Indonesia's disaster agency said the figure was based on estimates from local heads in the Petobo and Balaroa areas of the city, where entire neighbourhoods disappeared in the twin disaster on Sulawesi island that has seen 1,763 bodies recovered so far.

"Based on reports from the heads of Balaroa and Petobo, there are about 5,000 people who have not been found," agency spokesman Sutopo Purwo Nugroho told reporters Sunday, adding that it was difficult to know the exact figure given the areas were largely buried under mountains of mud and wreckage.