Torrential rain since late Tuesday triggered flooding across four districts of Bali, forcing the evacuation of 85 people, National Disaster Mitigation Agency (BNPB) spokesperson Abdul Muhari said in a statement.

Flash flooding also struck East Nusa Tenggara Province's Flores island on Monday, cutting road access and phone services in 18 villages, Abdul said in a separate statement.

Both floods were fatal, according to agency chief Suharyanto.

"In Bali, namely in Jembrana district... two people died. And in East Nusa Tenggara, in the Nagekeo district, four people died and four are still missing," said Suharyanto, who, like many Indonesians, goes by one name.

He added that parts of Bali were still inundated as of Wednesday, while water had receded on Flores.

The annual monsoon season, typically between November and April, often brings landslides, flash floods and water-borne diseases.

Climate change has affected storm patterns, including the length and severity of the season, leading to heavier rain, flash flooding and stronger wind gusts.

In March, floods and landslides on Java island killed three people and left five others missing after heavy rain inundated two dozen towns.

In January, at least 25 people died after floods and landslides hit a town in Central Java.