VICTIMS of the devastating tsunami and earthquake in Indonesia have been placed side-by-side in a 100-metre mass grave dug for 1,300 bodies.

Giant diggers covered the bodies in dirt and rubble as the death toll continues to climb - with thousands more feared buried under mud after the quake "turned the ground to liquid".

The 100-metre-long dirt and rubble trench has been dug in Palu and can be enlarged if needed, said Willem Rampangilei, chief of Indonesia's National Disaster Mitigation Agency.

Palu, on the island of Sulawesi, was hit by waves up to 20 feet high that crashed onto the shoreline where thousands had gathered for a beach festival at dusk last Friday.

The city was a crumpled mess of houses, cars and trees mashed together by the magnitude-7.5 quake, with rooftops and roads split and left at all angles.

Sutopo Purwo Nugroho, a spokesman for the national disaster mitigation agency, initially said 832 were killed but this was later revised to 1,203, with the death toll expected to climb.

He said: "The death is believed to be still increasing since many bodies were still under the wreckage while many have not been able to be reached."

Today's mass burial of earthquake and tsunami victims had to be carried out "as soon as possible for health and religious reasons", said the disaster mitigation agency.

Indonesia is majority Muslim, and religious custom calls for burials soon after death, typically within one day.

Army Commander Tiopan Aritonang said 545 bodies would be transferred from one hospital alone to the 10 metres-by-100-metres (33 ft by 330 ft) trench in Palu.

All of the victims have been photographed to help families locate where their relatives were buried.

Residents trying to track down their loved ones have been walking from body bag to body bag, opening the top to check who is wrapped inside.

After volunteers laid bodies inside the trench, mechanical earth-movers pushed soil on top of them.

More burials are expected to follow, as hundreds of people are still reported missing.

It is also feared that about 2,000 people are dead after mudslides swamped villages further inland, with Petobo resident Yusuf Hasmin telling the Jakarta Post that mud rolled in ‘like waves’.

National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho told reporters yesterday that soil liquefaction had occurred, where severe shaking from such a strong earthquake turns earth into mud.

The phenomenon occurs when loose water-filled soil near the surface loses its strength and collapses.

Nugroho said authorities estimate that "there are still hundreds of victims buried in mud" in Petobo. Rescue teams are trying to dig the victims out.

About 100 Indonesian troops were today expected to join about 1,300 personnel – including military and police – to help rescue efforts in Palu and Donggala.

They are bringing food, water and other supplies to the affected area, reports Associated Press.

Among those rescued over the weekend was a 25-year-old woman who was found alive in Palu on Sunday evening in the ruins of the Roa-Roa Hotel.

Search and rescue spokesman Sutopo Purwo Nugroho said most of the 61 foreigners visiting Palu at the time of the disaster have been accounted for, but one South Korean is believed to be trapped in Roa-Roa Hotel, while three others from France and one from Malaysia are still missing.

Rescuers have also managed to free a 15-year-old girl, Nurul Istikharah, who was unable to move her legs, as she was trapped under concrete beside her dead mother and niece.

Istikharah was unconscious during part of the effort to free her, but rescuers kept talking to her to try to keep her awake.

Nearly all the disaster’s deaths have been recorded in Palu, which has a population of 350,000, but 11 fatalities have been recorded nearby in Donggala.

Indonesian President Joko Widodo toured Palu on Sunday and tweeted: "Grieve for the people of Central Sulawesi, we all grieve together."

The city is built around a narrow bay that magnified the force of the tsunami waters as they raced into the tight inlet.

The updated death toll comes after Indonesian vice-president Jusuf Kalla said the number of fatalities could soar into the "thousands".

Aid and supplies have been sent in via military and commercial aircraft, including helicopters, to reach badly affected areas.

Donggala, the site closest to the earthquake's epicentre, and Mamuju were also ravaged, but little information has been available to victims due to damaged roads and disrupted telecommunications.

Desperate survivors have been forced to loot shops for basics like food, water and fuel as police looked on, unwilling or unable to intervene.

"There has been no aid, we need to eat. We don't have any other choice, we must get food," one man in Palu told AFP as he filled a basket with goods from a nearby store.

Meanwhile, government officials said some 1,200 inmates fled at least three prisons in the region.

Residents were also seen returning to their destroyed homes, picking through waterlogged belongings, trying to salvage anything they could find.

Others chose to flee the city and with roads soon becoming clogged with traffic jams.

Dwi Haris, who suffered a broken back and shoulder in the chaos, broke down as she described the ordeal.

"There was no time to save ourselves. I was squeezed into the ruins of the wall, I think," she said.

"I heard my wife cry for help, but then silence. I don't know what happened to her and my child. I hope they are safe."

Associated Press reports that when the 7.5 quake hit just after 6pm on Friday, the meteorology and geophysics agency issued a tsunami alert, warning of potential for waves of 0.5 to three metres (two to 10 feet).

But it was heavily criticised for ending the warning too soon, at 6.36pm, particularly as the waves were considerably higher.

The tsnumai was the latest natural disaster to hit Indonesia, which is frequently struck by earthquakes, volcanic eruptions because of its location on the "Ring of Fire," an arc of volcanoes and fault lines in the Pacific Basin.

In December 2004, a massive magnitude 9.1 earthquake off Sumatra island in western Indonesia triggered a tsunami that killed 230,000 people in a dozen countries.

Last month, a powerful quake on the island of Lombok killed 505 people.