The death toll from the quake and tsunami has exceeded 1,400 and is expected to rise and possibly hundreds of thousands have been displaced from their homes.
Amid the destruction, the information ministry has debunked “hoax news”.
Hoaxes include news of free flights being available to Palu for families of the victims and that the Bili Bili dam in South Sulawesi was cracking.
The police say they wasted time and resources checking out the dam hoax and said that officers “know the identities” of those spreading the rumours.
Photos from the 2004 Aceh tsunami have also been passed off as from last week.
The Indonesian government has already targeted the problem of fake stories, saying it will hold a weekly briefing to help the public “sort through the news”.
Hoaxes can be expected to multiply in the buildup to the presidential election next year.
The information ministry said rumours of the mayor of Palu’s death were exaggerated. “In fact, Palu Mayor Hidayat did not die and is now carrying out emergency work in Palu, Central Sulawesi,” it stated.
It is thought the story about a stronger earthquake is to enable thieves to raid abandoned homes.
According to islanders, hoaxes are mostly being spread verbally, as electricity supplies remained disrupted.
Food, water, fuel and medicine are reaching the hardest-hit areas outside Palu and the UN has warned of “vast” unmet needs.
More than 66,000 homes were destroyed or damaged by the magnitude-7.5 quake and subsequent tsunami on Friday with the UN’s humanitarian office saying almost 200,000 people needed urgent help.
Many rumours relate to the eruption of the Soputan volcano on Sulawesi, almost 1,000km from Palu (pictured), the city at the epicentre of Friday’s earthquake. It did erupt but photos and videos were falsified to make it seem far more serious than it was.
One photo showed a cloud of ash moving down a street, which came from South America, according to Dr Sutopo Purwo Nugroho of Indonesia’s BNPB disaster agency.
“This video is a hoax,” he said of one video showing drivers fleeing an eruption. “Ignore and do not share on social media.”
Meanwhile, the police say they have identified and plan to arrest four residents of Majene in West Sulawesi whom they suspect initiated the hoaxes.
Damage in Palu, Sulawesi. Picture credit: YouTube