Japan's government says at least 200 people have been confirmed dead after heavy rain last week triggered widespread flooding and landslides in western Japan.

Japanese Prime Minister Shinzo Abe told ministers at a taskforce meeting in Tokyo on Thursday that many more were still missing.

Tens of thousands of rescue and recovery workers and volunteers continued to dig through the debris to look for those still unaccounted for.

Record-setting rainfall caused severe flooding and landslides, toppling and burying homes across a wide area.

Most of the deaths were in Hiroshima and the surrounding area.

About 7,000 people have taken refuge at evacuation centres.

Roads and railway tracks have been damaged, disrupting land transportation and delaying delivery of food supplies and relief goods into the hard-hit areas.