As the death toll in Indonesia nears 1000, a 21-year-old air traffic controller is being hailed a national hero after he sacrificed his life to ensure a passenger jet carrying hundreds could safely escape Saturday’s earthquake.

Anthonius Gunawan Agung was the only person who stayed in the control tower at the Air Traffic Tower of Mutiara Sis Al Jufri Airport in Palu when the magnitude-7.5 quake struck the coastal city.

His colleagues had run for their lives when the tower started to sway and walls started to crack, but Mr Agung stayed to make sure Batik Air Flight 6321, which was on the runway at the time, took off safely.

He was just weeks away from his 22nd birthday.

Soldiers salute as the young man’s body is carried past. Photo: AirNav Indonesia

“When the earthquake occurred, Agung had cleared Batik Air for take-off. He waited until the aircraft was safely in the air before leaving his air traffic controller cabin,” AirNav Indonesia spokesman Yohanes Sirait said in a statement.

“He gave clearance for this flight, and if he left his post before the plane was airborne, hundreds of people inside the plane might be in danger.”

As the earthquake struck, Mr Agung jumped from the fourth floor of the control tower, suffering major injuries to his legs, arms and ribs, another AirNav spokesman told The Jakarta Post. He later died in hospital.

“We prepared a helicopter from Balikpapan in Kalimantan to take him to a bigger hospital in another city,” AirNav’s Mr Sirait said.

“Unfortunately we lost him this morning before the helicopter reached Palu.

“Our heart breaks to hear about this.”

Mr Agung stayed in this collapsing tower until the plane was clear. Photo: AirNav Indonesia

Australia has offered Indonesia whatever help it needs as disaster officials expressed fears the death toll from the earthquake and resulting tsunami might ultimately be “measured in the thousands”.

National Disaster Mitigation Agency (BNBP) spokesperson Sutopo Purwo Nugroho announced at a press conference about 5pm on Sunday (Australian time) that the death toll from the Sulawesi earthquake and tsunami has increased to 832.

He said 87 bodies had been identified by national police on Saturday, and bodies were already being buried in mass graves in line with Islamic burial rites.

Fearing much worse to come, Mr Sutopo said the affected area was much bigger than originally thought, and access to the worst-hit area of Donggala was restricted.

Mr Supoto addresses media during an update on Sunday evening. Photo: YouTube

The Donggala death toll was 11 at this stage, but it was expected to rise sharply once rescue teams reach the area.

There are 261 people being treated at Bhayangkara Hospital in Palu and that figure was getting higher by the hour, he said.

Shedding light on the scope of the disaster, Mr Sutopo said there was no electricity as five power stations had been damaged and that the water supply had been crippled by damage to pipes.

There is also limited fuel for vehicles.

Describing how waves in the tsunami were up to six metres high, Mr Sutopo said many obstacles remained in limiting access for heavy equipment to assist in rescue efforts of those trapped in the rubble of collapsed buildings.

Up to 50 people remain buried under the 10-storey Palu hotel. Photo: Getty

This includes 50 people buried under the ruins of the 10-storey Roa-Roa Hotel in Palu City. Six survivors were rescued from the wreckage.

A search-and-rescue team co-ordinated by the disaster agency is continuing its search for survivors in the aftermath of the earthquake.

Mr Sutopo said 61 foreign nationals were in the city of Palu at that time, but three French people, one Malaysian and one South Korean remain missing.

Access to Donggala, as well as the towns of Sigi and Boutong, is still limited, Mr Sutopo said, and there are no comprehensive reports from those areas.

At least another 500 people have been seriously injured after the quake brought down buildings and then sent a tsunami barrelling into the Indonesian island of Sulawesi on Saturday.

Prime Minister Scott Morrison called Indonesian President Joko Widodo on Saturday night to express his sympathies and pledge support.

“If he needs our help, he’ll have it,” Mr Morrison told the ABC on Sunday.

People loot a Palu convenience store on Sunday. Photo: AFP/Getty

Opposition Leader Bill Shorten said the Sulawesi disaster was particularly tragic because it came so soon after last month’s Lombok earthquake.

“Labor stands with the government in offering whatever support is needed to help the people of Indonesia recover from this tragedy,” he said.

Scenes of grief and horror are unfolding as rescuers try to bring a semblance of organisation to chaotic relief efforts after the 7.5-magnitude earthquake triggered a three-metre tsunami that rolled ashore and swept all before it.

“Many bodies” have been found along the shore of the Indonesian city of Palu, officials have confirmed.

Meanwhile shattered communications links, downed bridges and washed-out roads are hobbling efforts to get the rescue effort moving at top speed.

“We have not received comprehensive reports yet because communications are cut,” National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho on Saturday.

“Many bodies were found along the shoreline because of the tsunami, but the numbers are still unknown.”

As Saturday night descended on the shattered island, rescuers were struggling to get a full picture of the destruction even as more bodies were pulled from the rubble.  Rescue efforts were made even more hazardous by ongoing aftershocks threatening to bring down partially collapsed buildings.

Amateur footage shown by local TV stations showed waters crashing into houses along Palu’s shoreline, scattering shipping containers and flooding into a mosque in the city.

Harvest of death: A carpet of corpses wait to be identified and claimed in a makeshift morgue in Palu.

Indonesia’s meteorology and geophysics agency BMKG spokesperson Dwikorita Karnawati described the situation as “chaotic”.

Residents of the resort town ran for their lives as the tsunami surged into Palu and nearby Donggala, a fishing village closest to the epicentre of the quake.

The death toll is expected to rise even further, with local officials reporting that more victims are being found as frantic efforts to find survivors beneath fallen buildings continue.

“The situation is chaotic, people are running on the streets and buildings collapsed. There is a ship washed ashore,” said meteorology and geophysics agency BMKG spokesperson Dwikorita Karnawati.

She said the tsunami warning triggered by the earthquake, in place for about half an hour, was lifted after the tsunami was over.

Rescuers noted that Palu was a victim of geography. As the tidal wave entered the narrow bay it was “squeezed” at the sides and forced into a much higher wave, with some eyeweitnesses insisting it was all off six metres when it hit the town.

The narrow bay turned big waves into monstrous destroyers of life and property. Photo: Google maps

Mr Sutopo said the region is home to about 600,000 people, with thousands now left homeless and entire families appearing to have been swept from the face of the earth.

Mirza Arisam, a resident of Kendari, the capital of neighbouring Southeast Sulawesi, said his uncle and his family of five, including three children, were on vacation in Palu and he has been unable to contact them since the tsunami hit.

Mr Nugroho said the military was deploying troops to Palu and Donggala and the national police were also mobilising to help the emergency response, along with personnel from the search-and-rescue and disaster agencies.

“The cut to telecommunications and darkness are hampering efforts to obtain information,” he said.

“All national potential will be deployed, and tomorrow morning [Saturday] we will deploy Hercules and helicopters to provide assistance in tsunami-affected areas.”

Palu’s airport halted operations ours due to earthquake damage but has since reopened, allowing relief flights and emergency to be air-freighted to the heart of the disaster zone.

After the 7.5-magnitude earthquake struck, television footage showed people running into the streets.

Video posted on Twitter by the BNPB showed women and children crying hysterically as they ran out of their homes and shops.

Rumah dan bangunan banyak yang mengalami kerusakan akibat gempa 7,7 SR di Kota Palu dan Donggala Sulawesi Tengah. Berdasarkan analisis gempa dirasakan intensitas gempa VI-VII MMI (keras hingga sangat keras). Biasanya bangunan banyak yang roboh. Evakuasi masih dilakukan. pic.twitter.com/7yCf2sMAwL

— Sutopo Purwo Nugroho (@Sutopo_PN) September 28, 2018

“It was so strong. The strongest I ever felt. We all ran out of buildings,” said Yanti, a 40-year-old housewife in Donggala who goes by a single name.

“All the things in my house were swaying,” another Donggala resident, Mohammad Fikri, said of the earlier 6.1 quake.

UN spokesman Stephane Dujarric said UN officials were in contact with Indonesian authorities and “stand ready to provide support as required”.

-with agencies