Millions flee as Japan floods and landslides kill at least 85

Dozens dead and missing as 'historic rains' and floods hit Japan

Flooding and landslides have killed at least 76 people and left dozens missing.

"We've never experienced this kind of rain before", an official at the Japanese Meteorological Agency (JMA) told media.

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

"Our thoughts are with you and the people of Japan during this hard period", PM Lee wrote in a letter to his counterpart, Mr Shinzo Abe.

Japan's Meteorological Agency retained special weather warnings for three prefectures in the main island of Honshu, down from five, and urged vigilance against landslides, rising rivers and strong winds amid what it called "historic" rains.

Chief Cabinet Secretary Yoshihide Suga said around 48,000 police, fire fighters and members of Japan's Self-Defence Forces were responding to more than 100 landslides and other appeals for help.

Rescue workers dug through landslides that crushed houses in the same region, while several people evacuated to their rooftops as floods swamped entire residential areas in part of the Okayama region.

People wait to be rescued on the roof of a house nearly submerged in floodwaters caused by heavy rains in Kurashiki, Okayama prefecture, southwestern Japan on Saturday.

"Water came to the middle of the second floor", a woman in Kurashiki, Okayama Prefecture, wrote, posting a picture of her room half swamped by flooding.

Evacuation orders went out in some outlying parts of Kyoto, with the Kyodo news agency saying about 16,000 people were affected. Seven homes were destroyed, dozens more were damaged, while more than 570 were flooded.

Prime Minister Shinzo Abe warned of a "race against time" to rescue flood victims, some of whom have resorted to tweeting desperate messages seeking help from emergency services.

Most of the deaths have occurred in Hiroshima prefecture, which has been hit by torrential rain since Thursday.

Also in Ehime, two primary school girls and their mother who got sucked into a mudslide were rescued but their hearts were not beating, a report said.

According to the Ministry of Land, Infrastructure, Transport and Tourism, 17 railroad operators were suspending services on 56 routes in western Japan or elsewhere.

The worst hit region by the flood was in the southern area of Hiroshima prefecture, where a landslide struck a public housing complex in Hiroshima City and inundated about 20 buildings, according to NHK.

Automakers including Mazda Motor Corp and Daihatsu Motor Co suspended operations at several plants on Saturday and were to decide later on Sunday on plans for the coming week.

Throughout the affected areas, parked cars sat in pools of water.

A kimono-clad woman using a smartphone takes photos of swollen Kamo River, caused by a heavy rain, from Shijo Bridge in Kyoto, Japan July 5, 2018.