Death toll in Indonesia quake-tsunami hits 420

As stunned people on the stricken island of Sulawesi struggled to find food and water, looting has started to spread and fears are growing that whole towns have still not been heard from.

Indonesian vice-president Jusuf Kalla said the toll could reach "a thousand, thousands" based on previous disasters.

State media reported that the death toll had increased to 420 with a further 540 serious injured, but those figures were for Palu alone and relief agencies expressed fears that the number could spike once news started coming in from other affected areas.

"Worryingly, the National Disaster Management Agency has said they've received no information from the district of Donggala, which is closer to the epicentre of the earthquake," said Helen Szoke of Oxfam, referring to a region that is home to around 300,000 people. 

In the coastal city of Palu on Sunday aid was trickling in, the Indonesian military had been deployed and search-and-rescue workers were doggedly combing the rubble for survivors - looking for as many as 150 people at one upscale hotel alone. 

There were also concerns over the whereabouts of hundreds of people who had been preparing for a beach festival when the 7.5-magnitude quake struck Friday, sparking a tsunami that ripped apart the city's coastline.

Amid the levelled trees, overturned cars, concertinaed homes and flotsam tossed up to 50 metres inland, survivors and rescuers struggled to come to grips with the scale of the disaster.

C-130 military transport aircraft with relief supplies managed to land at the main airport in Palu, which re-opened to humanitarian flights and limited commercial flights, but only to pilots able to land by sight alone.

Satellite imagery provided by regional relief teams showed the severe damage at some of the area's major sea ports, with large ships tossed on land, quays and bridges trashed and shipping containers thrown around.

Hospitals were overwhelmed by the influx of those injured, with many people being treated in the open air. There were widespread power blackouts.

Indonesian president Joko Widodo was expected to travel to the region to see the devastation for himself on Sunday.