At least eight people were killed on Saturday when a hot-air balloon with 21 passengers caught fire in southern Brazil, a state governor said.

It was the second fatal balloon accident in the country in less than a week.

"Eight fatalities and 13 survivors," Santa Catarina state governor Jorginho Mello said on X.

Videos taken by bystanders and carried on Brazilian television showed the moment when the balloon erupted in flames above a rural area outside the Atlantic coast town of Praia Grande, a tourist hotspot popular for hot-air ballooning.

The basket carrying the passengers plummeted dozens of metres to the ground in flames. Other images showed some of the passengers jumping.

The 13 survivors were treated at hospitals, firefighters said.

Officials at Our Lady of Fatima hospital said of the five survivors treated there, three were in stable condition with minor injuries and two had already been discharged.

Information about the other survivors was not immediately available.

An investigation was launched to determine the cause of the accident. Weather conditions were clear at the time. (AFP)