The jump in the official death toll from 844 on Monday is line with earlier warnings and it could still reach into the thousands as rescuers to push out from Palu and into harder to reach places like Donggala and Sigi.

And while the Indonesian government has agreed to accept international assistance following the magnitude 7.5 earthquake and six metre tsunami – unlike after the Lombok earthquake – this aid has been delayed as negotiations continue in Jakarta over what will be accepted.

National Disaster Management spokesman Sutopo Purwo Nugroho said the dead were from Palu, Donggala, Sigi and Parigi Moutong.

As of Tuesday afternoon, disaster agency estimated 99 people were missing, 799 were badly injured, 152 victims remained trapped under debris, there were 61,687 refugees created by the earthquake and tsunami and 65,733 houses had collapsed.

“Again, not all refugees’ needs are being met. Fuel, clean water, sanitation, food and tents are still in short supply even though supplies keep coming,” he said in Jakarta.

“We have buried 153 bodies yesterday in several cemeteries. Today we have prepared 15 trucks and 1000 body bags for mass burial purposes. But we don't know how many bodies will be buried.”

Sutopo said any assistance from other countries should be self-supporting and that “we need Hercules C130 [aircraft] in this case” – an aircraft the Australian air force operates.

Twenty-six countries have offered assistance, including Australia, the US, South Korea, China and Singapore, and once negotiations are finalised in Jakarta more significant aid will begin to flow.

Co-ordinating minister for Legal, Political and Security Affairs Wiranto later said that Singapore and Malaysia would send two or three C-130 Hercules planes.

He declined to give details on the aid that would come from other countries, including Australia.

He added that "we have fixed two main power generators and five others are still being fixed. More power generators are coming in but if we still need more power we can send the mobile power ship we hired from Turkey, which is currently in Kupang."

On the outskirts of Palu, lorries brought bodies for burial in a mass grave dug in sandy soil. Some relatives turned up at the 50-metre trench where the smell of decomposition was overpowering.

There is particular concern about Donggala, which is home to about 270,000 people north of Palu and which was closer to the epicentre.

Initial reports from Red Cross rescuers who had reached the outskirts of Donggala district were chilling.

"The situation in the affected areas is nightmarish," Jan Gelfand from the Red Cross/Red Crescent Jakarta office said.

Sutopo said 6399 evacuation workers, from the military, police and volunteers, were in the disaster zone, while helicopters which were fighting fires in Kalimantan had been redeployed.

Indonesian President Joko “Jokowi” Widodo was due to visit the disaster zone for the second time in five days on Tuesday.

At a meeting at the Presidential Palace on Tuesday morning, Widodo said the clean up of Palu needed to be finished more quickly.

He also asked his police chief to arrest people who were creating unrest in the devastated community.

After food and water, which authorities have been distributing to refugees in Palu, petrol is the most precious commodity.

There are long lines outside petrol stations all day and into the evening, and Fairfax Media has witnessed fights break out between people over their five-litre ration.

Sutopo said 10 more tankers carrying fuel had arrived in the city on Tuesday, while more had been flown in by air.

“All vehicles bringing logistics are guarded by TNI [the military] and police… there were several incidents in previous days,” Sutopo said.

Power is mostly still out in this city of 330,000 people, except for emergency services who have generators, and tens of thousands of people are sleeping outside either their homes, or outside government buildings including the offices of the mayor and local governor.

Nearly four days after the devastation of Friday night, the chances of finding anymore survivors trapped in the rubble of are growing slim.

Despite this, Agus Haryono, the head of a local rescue team, told Reuters he was still hopeful of pulling more people out alive from the seven-storey Hotel Roa Roa, which had collapsed.

About 50 people were believed to have been trapped when the hotel was brought down by the 7.5 magnitude earthquake.

Fairfax Media spent the morning with a team of 12 volunteers from the Indonesian island of Java who were combing the Talise beachfront, near the centre of Palu, for bodies.

In three hours they found two more bodies on the beachfront, which was ground zero when the tsunami swept through on Friday evening.

In the next four hours, according to team leader Yoni [just the one name], his team found three more dead bodies. They were not expecting to find any survivors.

Australia has promised $500,000 to help the victims in Palu, Sigi, Donggala and the surrounding region.

Prime Minister Scott Morrison said the initial funds would go to the Indonesian Red Cross for crucial items like tarpaulins but there was more to come to help with the “significant crisis”.

"Australia has expertise and resources in particular areas where it can deploy, and we're looking to see how we can best fit the need to ensure that we can do whatever we can to support our Indonesian friends and neighbours in this time of very genuine need.

"Our ambassador has been working closely with the Indonesian government had to look at a second round of support," he said at a doorstop in Guildford, Western Australia on Tuesday.

Oxfam and its partner organisations are getting ready to help 500,000 people after the Indonesian Government announced more than 2 million people could be affected by the earthquakes and tsunami.

To donate, visit Red Cross Indonesia Earthquakes and Tsunami Appeal, Oxfam Australia, care.org.au/tsunami or call 1800 020 046

- with Reuters, AP, Dana McCauley

To donate, visit Red Cross Indonesia Earthquakes and Tsunami Appeal, Oxfam Australia, World Vision, CARE Australia