The death toll of an earthquake and tsunami in Indonesia has soared to 832, with authorities fearing the numbers will climb as rescuers struggle to get aid to outlying communities cut off from communications and help.

Dozens of people are reported to be trapped in the rubble of several hotels and a mall in the city of Palu, on Sulawesi island, which was hit by waves as high as six metres following the 7.5 magnitude earthquake on Friday.

Australia’s Prime Minister Scott Morrison and Foreign Affairs Minister Marise Payne expressed their condolences to the people of Indonesia in a joint statement late on Sunday.

They said Australia stands ready to support the Indonesian government’s response efforts if needed.