Japan has deployed tens of thousands of troops and rescue workers after one of the strongest storms in years hit, killing at least 23 people.

Typhoon Hagibis made landfall south of Tokyo on Saturday, moving north and bringing severe flooding. Seventeen people are missing from the storm, public broadcaster NHK said.

In central Nagano prefecture, water surrounded Japan's famous bullet trains while helicopters plucked stranded residents from rooftops. A total of 27,000 military troops and other rescue crews have been deployed in relief operations, authorities said.

 "The government will do its utmost," Prime Minister Shinzo Abe said, promising to deploy more troops if needed. By Sunday the storm had weakened and moved off land.

 In Kawagoe city, north of Tokyo, emergency crews used boats to help residents trapped in a nursing home. Nearly 150,000 homes in the greater Tokyo area are without power with running water also hit. Train and flight services cancelled under the threat of Hagibis are resuming. Many of the deaths came as people were buried in landslides or swept away by floodwaters. Some areas of Japan saw up to 40% of their average rainfall in just a few days.