At least 200 people have died following sustained heavy rainfall in western and central Japan, causing flash flooding, landslides and submerged floodplains.

More than 2 million people – mostly from the Hiroshima and Okayama prefectures – have been forced to evacuate their homes, with dozens  missing in Japan’s worst weather-related disaster in 36 years.

More than 70,000 military, police and fire fighters are toiling through the debris and mud in a grim search for the missing.

Members of a police rescue team search for missing people at a flood hit area in Sakacho, Hiroshima prefecture on July 13, 2018. Photo: Getty

A traditional Japanese gate most commonly found at a Shinto shrine, is seen in a flood hit area in Sakacho, Hiroshima prefecture on July 13, 2018. Photo: Getty

An aerial photo taken with a drone shows the reconstruction site of a damaged embankment and road due to recent heavy rains and flooding, in the Mabicho area in Kurashiki, Okayama prefecture on July 12, 2018. Photo: Getty

Members of Maritime Self Defense Forces search for missing persons at a flood damage site in Kure, Hiroshima prefecture on July 12, 2018. Photo: Getty

Residents remove mud from a damaged house in a flood hit area in Kurashiki, Okayama prefecture on July 13, 2018. Photo: Getty

Evacuated residents at a makeshift shelter in Mabi, Okayama prefecture on July 11, 2018. Photo: Getty

Residents rescue dogs from flooded area in Kurashiki, Okayama prefecture on July 8, 2018. Photo: Getty

Residents try to upright a vehicle stuck in a flood hit area in Kurashiki, Okayama prefecture on July 9, 2018. Photo: Getty

A woman walks past rubbish piled up after the recently flooding as the clean up continues in Mabi, Okayama prefecture on July 11, 2018. Photo: Getty

Police arrive to clear debris scattered on a street in a flood hit area in Kumano, Hiroshima prefecture on July 9, 2018. Photo: Getty

Meanwhile displaced residents are sweltering in school gymnasiums and evacuation centres, with only paper fans and floor mats to keep them comfortable as daily temperatures exceed 30 degrees.

More than 200,000 households had no water on Thursday, a week after torrential rains destroyed decades-old communities built on mountain slopes and flood plains.

Authorities have warned the limited water supply is putting people at risk of suffering heatstroke and some fear disease epidemics with few using accessible water to wash their hands.

The government has sent water trucks to the disaster area, but supplies remain limited.

“It’s an undeniable fact that this sort of disaster due to torrential, unprecedented rain is becoming more frequent in recent years,” Chief Cabinet Secretary Yoshihide Suga said at a news conference in Tokyo.

–with AAP