The death toll from the midweek landslides in southwestern Japan has risen, as fresh rain stoked fears of more disasters and hampered the round-the-clock search for survivors.

The body of a 83-year-old man was found early on Sunday, raising the death toll to 50, a prefectural police spokesman said.

The regional police headquarters in Hiroshima said that 38 other people remained unaccounted for, four days after unusual downpours triggered landslides that swallowed dozens of homes, many of them perched on hillside housing areas.

A total of about 3,000 rescuers including ground troops, fire fighters and police continued digging through mud and debris.

But the search and rescue operation overnight was halted at around dawn on Sunday as fresh rain raised concerns about more landslips, public broadcaster NHK reported.

Japanese Prime Minister Shinzo Abe and his cabinet have set up a taskforce in response to the disaster.

"We hereby gather to set up an emergency taskforce and we are determined to accelerate to provide the comprehensive support which is required."

About 1,700 people remained sheltered at 13 safe public facilities while the Hiroshima city government upheld evacuation orders and warnings for 164,000 residents in the disaster areas.

"I wish I get some place today. It doesn't look like my house will be in any condition that we can go back," an unidentified resident told the Associated Press news agency.

With land in short supply in many parts of Japan, cities often expand into mountainous areas, leaving such development vulnerable to landslides.

Hiroshima was hit by landslides in 1999 that claimed the lives of 31 people.

Source: Agencies