Rescue officials fear the full scale of Indonesia’s earthquake and tsunami could climb far past the more than 800 already confirmed dead.

The country’s disaster agency said the death toll more than doubled to 832, and nearly all of those were from the hard-hit city of Palu on the island of Sulawesi.

A motorbike passes the wreckage of a car in Palu A motorbike passes the wreckage of a car in Palu (AP Photo/Tatan Syuflana)

The regencies of Donggala, Sigi and Parigi Moutong — with combined populations of 1.2 million — had yet to be fully assessed.

Several large coastal towns remain cut off by damaged roads and downed communication lines.

“The death toll is believed to be still increasing since many bodies were still under the wreckage, while many have not been reached,” said agency spokesman Sutopo Purwo Nugroho.

He said a mass burial would be held on Sunday for health reasons.

(PA Graphics)(PA Graphics)

Bodies covered in blue and yellow tarps lined the streets of Palu, while rescuers dug through rubble in the hopes of finding survivors from the twin disasters that struck on Friday evening.

There was particular focus on the eight-storey Roa-Roa Hotel, where voices from underneath the rubble could be heard calling out for help on Saturday.

The cries from beneath the hotel, which appeared to have collapsed, had gone silent by Sunday afternoon. Officials had estimated some 50 people could be inside.

“We are trying our best. Time is so important here to save people,” said Muhammad Syaugi, head of the national search and rescue team. “Heavy equipment is on the way.”

A mosque was badly damagedA mosque was badly damaged (AP Photo/Tatan Syuflana)

TV footage showed about a dozen rescuers in orange jumpsuits climbing over debris with a stretcher carrying the body of a victim from the modest business hotel.

Aid and supplies were being sent to the area via military and commercial aircraft, including helicopters, to reach badly affected areas. Officials said the area was lacking medical supplies, fuel, fresh water and experts.

Indonesian President Joko “Jokowi” Widodo toured Palu on Sunday.

“There are many challenges,” he said. “We have to do many things soon, but conditions do not allow us to do so.”

Mr Nugroho said 61 foreigners were in Palu at the time of the disaster. Most of them had been accounted for, but one South Korean was believed to be trapped in the ruins of the Roa-Roa Hotel, while three others from France and one from Malaysia were missing. The survivors were to be evacuated to the Sulawesi city of Makassar in the island’s far south.