Floods that have killed more than 20 people forced the closure of Kochi international airport Friday as the south Indian state of Kerala confronted a second straight year of crisis level downpours.

Low-lying areas in Diva flooded after heavy rain and discharge from Barvi Dam into Ulhas river on August 5, 2019 in Thane, India. (Photo: VCG)

The main airport for the popular tourist state will remain closed until at least Sunday, authorities said, as rising waters took over the runways.

With predictions of freak rains continuing for several days, Kerala's chief minister Pinarayi Vijayan warned the public that dam gates may have to be opened soon.

More than 20 landslides had already been reported and high level alerts ordered in nine districts, he said, adding that several people were feared trapped under the mud.

Officials said 22 deaths had been confirmed, but media reports gave a figure of 29 dead for just Thursday.

More than 23,000 people have already moved into 315 emergency camps set up across the state, Vijayan said.

Nearly 500 people died in the 2018 floods, believed to be the worst in a century.

Experts blamed the rising waters on deforestation and the state's rapid recent urbanisation, as well as poor management of the many dams.