Rescue efforts are underway to find survivors after Typhoon Hagibis left vast sections of towns in central and eastern Japan under water.
More than 110,000 police officers, fighter fighters, soldiers and coastguard personnel, as well as some 100 helicopters have been mobilised for Monday's rescue operations, officials added.
"There still are many residents who have yet to be accounted for. Our people in uniform are working day and night in search and rescue operations," Prime Minister Shinzo Abe told an emergency meeting of ministers.
"Damage has been made in an extremely wide range of areas, and more than 30,000 people are still being forced to remain in the state of evacuation."
Typhoon Hagibis made landfall on Japan's main island of Honshu on Saturday, leaving at least 40 people dead and 189 injured.

Israeli strike kills one in Gaza as sides trade blame for truce violations
UK police say mass stabbing on train not terrorist incident, two arrested
Israel urges Lebanon to disarm Hezbollah under ceasefire terms
Russian attacks on Ukraine kill two
Kenya landslide death toll rises to 22
Fire at store in northwestern Mexico leaves at least 23 dead
Ukrainian drone strike hits key Russian oil port
Tanzania's Hassan declared landslide winner in election marred by violence
