Floods and landslides in Indonesia have killed at least 59 people, the government said Friday, after heavy rain pounded Sulawesi island and forced thousands to flee their homes.

"I've never seen something this bad -- this is the worst," Syamsibar, head of South Sulawesi's disaster mitigation agency, told AFP, adding that 25 people were still missing.

Lashed by the heavy rain, rivers swelled and burst their banks, inundating dozens of communities in 11 districts of southern Sulawesi. Parts of the provincial capital Makassar have also been affected.

Gowa district suffered the heaviest casualties, with 44 people found dead, said Syamsibar, who like many Indonesians goes by one name.

Some 3,400 people were evacuated from their homes and given refuge in schools, mosques and tents.

Rescuers and residents waded through streets filled with waist-deep water, some carrying their possessions above their heads.

"I couldn't save all my belongings, my house was swept away," Makassar resident Ayu Fiskarina told AFP.

Authorities say floodwaters are receding but the impact of the disaster has ranged far and wide, damaging houses, government buildings, schools and bridges.

"All the locals in this area have been evacuated to the mosque, except for (a) woman who refuses to leave her house because she's scared her belongings could be looted," said Makassar police officer Ardal.

The death toll stood at 30 on Thursday evening.

Landslides and floods are common in Indonesia, especially during the monsoon season between October and April. Photo: AFP

Landslides and floods are common in Indonesia, especially during the monsoon season between October and April, when rains lash the vast Southeast Asian archipelago.

Last year, flash floods and landslides killed at least 22 people in several districts across Sumatra island, while a dozen died when an avalanche of mud and rock cascaded down a steep slope in central Java, Indonesia's main island.

In 2016, also in Central Java, about 50 people died when heavy downpours sent torrents of water, mud and rock into villages.

Indonesia is one of the most disaster-prone nations on Earth, straddling the Pacific Ring of Fire, where tectonic plates collide. Volcanic eruptions and earthquakes are common.

In December, more than 400 were killed in a volcano-triggered tsunami in western Java, while thousands died in a quake-tsunami disaster around the city of Palu on Sulawesi island in September.

Lombok, an island next to Bali, was rocked by earthquakes in the summer that killed more than 500 and sparked a mass exodus of foreigners from the tropical paradise.