Further four people were in cardiopulmonary arrest, he told reporters in Tokyo. Authorities in the Hiroshima prefecture could not confirm the whereabouts of 42 people, Suga said.
A total of 73,000 firefighters, police officers and soldiers are assisting in the relief efforts. Prime Minister Shinzo Abe this week visited the capital city of Okayama prefecture to assess the damage and is expected to make another trip to an affected region on Friday.
Previously, Shinzo Abe decided to cancel his state visits to Belgium, France, Saudi Arabia and Egypt amid the flooding and landslides in his country.