MUKOMUKO, Indonesia : The death toll from a series of major earthquakes striking Indonesia's Sumatra rose to 23 on Saturday, while officials tallied more than 15,000 collapsed or damaged buildings.

An initial 8.4-magnitude quake struck at dusk off Sumatra's west coast on Wednesday and was followed by a series of powerful aftershocks, jolting the coastal provinces of Bengkulu and West Sumatra most severely.

Rustam Pakaya from the health ministry's crisis centre told AFP the toll had risen to 23, with 88 wounded.

Rescue teams have been continuing their hunt for victims feared trapped under thousands of buildings toppled by the quakes, and many traumatised survivors have been too petrified to return to their homes.

In Bengkulu, nearly 2,000 houses were totally flattened and nearly 4,000 others badly damaged, said Bowo Santoso from the governor's disaster rescue centre. About 90 local hospitals and clinics were also damaged, he added.

In West Sumatra, more than 9,700 houses collapsed or were too badly damaged to be inhabitable, said Suryadi from the disaster rescue centre there. More than 100 mosques and about 20 school buildings were also damaged, he said.

Aid has been flowing to many of the affected areas, though some survivors had still not seen any of it.

Hercules transport planes were to try to drop aid on several islands in the Mentawai group off Sumatra, which were badly hit by the quake and a small tsunami, said an official in the city of Padang.

Frans Karel, an official on Pagai Utara island in the group, said no aid had yet been received and many frightened villagers were sheltering in the hills.

"We haven't yet received aid. All the kiosks have collapsed and their food stocks are wet," he told AFP by telephone.

"Almost 75 percent of houses on the coastline along a 10-kilometre (six-mile) stretch are badly damaged and collapsed."

In the city of Mukomuko, about 260 kilometres north of Bengkulu, residents were desperate for help.

"We have no rice, we have clothes, we have no kerosene. We want to buy supplies, but there is no one to sell them to us," 50-year-old resident Muslimar told AFP.

The scale of the damage, considering the initial quake's size and subsequent shocks, has been much lower than initially feared. The UN has said no international aid effort would be required to help with recovery efforts.

- AFP /ls