More than 1,200 people are now known to have died in the quake-tsunami that smashed into Sulawesi, Indonesia said Tuesday, as police pledged to clamp down on looting by survivors taking advantage of the chaos.

There were reports of officers firing warning shots and tear gas to ward off people ransacking shops in Palu, a coastal city ravaged by a 7.5-magnitude quake and the tsunami it spawned.

Almost 200,000 people are in need of urgent help, the United Nations says, among them thousands of children.

Survivors are battling thirst and hunger, with food and clean water in short supply, and local hospitals are overwhelmed by the number of injured.

Police said Tuesday that they had previously tolerated desperate survivors taking food and water from closed shops, but had now arrested 35 people for stealing computers and cash.

"On the first and second day clearly no shops were open. People were hungry. There were people in dire need. That's not a problem," said deputy national police chief Ari Dono Sukmanto.

"But after day two, the food supply started to come in, it only needed to be distributed. We are now re-enforcing the law."

"There are ATMs. They are open," he added. "If people steal, we catch and investigate."

Despite official assurances, desperation was evident on the streets of Palu, where survivors clambered through wreckage hunting for anything salvageable.

Others crowded around daisy-chained power strips at the few buildings that still have electricity, or queued for water, cash or petrol being brought in via armed police convoy.

"The government, the president have come here, but what we really need is food and water," Burhanuddin Aid Masse, 48, told AFP.

Rescue efforts have been hampered by a lack of heavy machinery, severed transport links, the scale of the damage, and the Indonesian government's reluctance to accept foreign help.

As if to remind the world of the tectonic fragility of Indonesia, a series of quakes hit the island of Sumba on Tuesday, albeit hundreds of kilometres from Palu.

The official death toll from the tragedy in central Sulawesi stood at 1,234, according to the government.

The Indonesian military is leading the rescue effort, but following a reluctant acceptance of help by President Joko Widodo, international NGOs also have teams on the ground in Palu.

Among the dead are dozens of students whose lifeless bodies were pulled from their landslide-swamped church in Sulawesi.

"A total of 34 bodies were found by the team," Indonesia Red Cross spokeswoman Aulia Arriani told AFP after the grim discovery, adding that 86 students had initially been reported missing from a Bible camp at the Jonooge Church Training Centre.

Indonesia is the world's most populous Muslim-majority nation but there are small pockets of religious minorities, including Christians, across the archipelago of 260 million people. (AFP)

•Members of an Indonesian rescue team search for victims from collapsed buildings in Palu in Central Sulawesi on October 2, 2018, after an earthquake and tsunami hit the area on September 28.

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