Rescue workers continue door-to-door search for dozens of missing after the worst weather-related disaster in the country in over three decades.

Residents cross an area still flooded in Kurashiki, Okayama prefecture on July 9, 2018.
Residents cross an area still flooded in Kurashiki, Okayama prefecture on July 9, 2018. (AFP)

The toll in record rains that have devastated parts of Japan has risen to 179, the government's top spokesman said on Wednesday morning.

Hopes of finding survivors were fading as rescue workers carried out house-to-house searches after days of deadly floods and landslides in Japan's worst weather-related disaster for decades.

The record downpours that began last week have stopped and receding flood waters have laid bare the destruction that has cut a swathe through the west of the country.

Japan's prime minister Shinzo Abe headed on Wednesday to one of the areas worst-hit by record rains.

Abe, who cancelled a four-stop foreign trip planned for this week as the disaster worsened, was due to visit the flood-ravaged Okayama area to see the scale of the damage first-hand.

Abe was scheduled to fly over the Mabi district to view the damage, and meet with evacuees and local officials to discuss their needs.

In the city of Kurashiki, the flooding engulfed entire districts at one point, forcing some people to their rooftops to wait for rescue.

Rescue workers were going door-to-door, looking for survivors -- or victims -- of the disaster.

"It's what we call a grid operation, where we are checking every single house to see if there are people still trapped inside them," an official with the local Okayama prefecture government told AFP.

"We know it's a race against time, we are trying as hard as we can."

Hideto Yamanaka was leading a team of around 60 firefighters dispatched from outside the prefecture searching homes.

"I'm afraid elderly people who were living alone may have failed to escape," said Yamanaka, 53.

"Physically weak people may have been late in getting out when it suddenly started raining hard, swamping the area," he told AFP.

As night fell, rescuers continued searches, "but we still don't know if we will carry out the operation around the clock," said Akiko Harada, a spokeswoman at the disaster management section of the city of Hiroshima, where 14 people were still unaccounted for.

Local residents retrieve belongings from their destroyed houses in a flooded area in Mabi town in Kurashiki, Okayama Prefecture, Japan.
Local residents retrieve belongings from their destroyed houses in a flooded area in Mabi town in Kurashiki, Okayama Prefecture, Japan. (Reuters)

In the Mabi district of Kurashiki, the water left behind a fine yellow silt that has transformed the area into moonscape.

Wearing masks

Cars driving through kicked up clouds of dust. People walking around wore medical masks or covered their mouths with small towels to protect themselves against the particulates.

Stores were still closed, and inside one barber's shop the red sofas, customer chairs, and standing hair dryers were all covered with the same silt.

Fumiko Inokuchi, 61, was inside her home, sorting through the damage caused by floods that submerged the entire first floor.

She escaped the house on Saturday, crossing the street to take shelter in a three-storey care home for the elderly, from where she watched in horror as the waters rose.

"I saw my house sink underwater and I couldn't do anything at all, there was just nothing I could do. I felt helpless," she said, retrieving a photo of her children playing baseball.

"I got married here, and we built this house two years afterwards. We raised our three small sons to adulthood here, there are so many memories," she said, her eyes welling with tears.

New dangers from heat

It is Japan's deadliest weather-related disaster in more than three decades, and has sparked national grief.

Top government spokesman Yoshihide Suga said on Tuesday that at least 156 people had been killed. Media reports said dozens more were missing and the toll was expected to rise further.

Around 75,000 police, firemen and troops have been deployed in the search and rescue operation across parts of central and western Japan, Suga said, warning that hot weather posed new risks.

Thousands of people remain in shelters, and local authorities in some areas were offering drinking water and bathing services for those without their own supply.

"It will be over 35 Celsius (95 degrees Fahrenheit) in some areas... Please be careful about heatstroke if you're doing reconstruction outdoors, and continue to be vigilant about landslides," Suga said.

The government said it would tap around $20 million in reserve funds to provide aid to those affected by the disaster.

And even with the rains over, the risk of flooding remained, with the town of Fuchu in Hiroshima issuing a new evacuation order as a local river burst its banks.

"Driftwood and dirt has piled up... and now the water has started overflowing from the river," a spokesman for the local fire department told AFP.

"We are on high alert," he added.

In Ehime prefecture, authorities said they were struggling to get emergency food and water to some cut-off areas.

"We are sending them by boat and air routes," said Yoshinobu Katsuura, a spokesman for the prefecture's disaster management department.

"It will take a lot of time to see devastated areas recover."

Source: TRTWorld and agencies