Torrential rainfall and flooding has battered a widespread area of south-western Japan, leaving at least 15 people dead and more than 50 missing, according to reports.

As the death toll climbed from the rainfall, which began earlier this week, Okayama prefecture said a man caught in a landslide had been pronounced dead.

Kyodo news service reported another death in a landslide in Hiroshima, which set off a fire, while the body of a child was found in a flooded area.

Residential buildings were damaged by a landslide in Hiroshima prefecture
Residential buildings were damaged by a landslide in Hiroshima prefecture (Kyodo News/AP)

Among the missing were five people who were buried when housing collapsed, also in Hiroshima prefecture.

In Ehime prefecture, a woman was found dead on the second floor of a home hit by a landslide, Kyodo said.

Yamaguchi prefecture, another area hit by the heavy rain, alerted people to heed evacuation warnings and act quickly.

Katsura river in Kyoto
Katsura river in Kyoto (Yosuke Mizuno/Kyodo News/AP)

Kyoto prefecture said it was working to control flooding at several dams. About 250 people had to flee their homes and the prefecture identified one fatality as a 52-year old woman.

Roads were blocked in some areas and warnings issued on landslides.

Military water trucks were rushing to areas where water systems were no longer working, Okayama prefecture said.

Although Japan is among the most modernised of Asian nations, rural areas are hit hard by the rainy season each year, often resulting in casualties and heavy damage.