A typhoon was churning off the Japanese coast Friday after injuring 18 people and forcing thousands of people to flee their homes, officials said.

Typhoon Usagi cut across the island of Kyushu and the tip of the main island of Honshu overnight and moved into the Sea of Japan (East Sea) early Friday while slowly weakening, the Japan Meteorological Agency said.

People walk against strong wind at Fukuoka city in Japan's southern island of Kyushu.

Television footage showed flooded rivers, uprooted trees and drenched people whose bicycles and umbrellas were blown away at the peak of the storm.

Japan's famed bullet trains ground to a halt between Honshu and Kyushu, with railway officials turning a train stranded in Hiroshima into a makeshift hotel where they served meals.

The typhoon still packed winds of up to 72 kilometres (45 miles) an hour late Friday as it moved northward at 126 kilometres (79 miles) an hour along Honshu's northern coast, the agency said.

The storm system was projected to reach the tip of the northern island of Hokkaido before on Saturday but to forecast into a moderate depression.

Usagi, which means rabbit in Japanese, hit Japan just two weeks after a killer typhoon ravaged nearby areas.

A total of 18 people were injured in the latest typhoon, police and municipal officials said.

"A gust made a 30-year-old man's postal delivery car tumble as he was backing up," hurting him in the stomach, said Yasuo Ishitomo, a crisis management official in Hiroshima prefecture.

An elderly woman was seriously injured in Kagoshima prefecture on the southern island of Kyushu.

"A sudden wind blew away the 81-year-old woman, breaking her left thigh," a municipal official said.

Among the other injured people was a 49-year-old woman whose index finger was chopped off as a gust slammed a door shut in the southern prefecture of Miyazaki.

A 52-year-old carpenter broke his right wrist as he fell from the roof of a house under construction while a 42-year-old man suffered head wounds when he fell three metres (10 feet) from the roof of his house.

Municipal governments advised tens of thousands of people to evacuate amid gusts and downpour. The storm triggered 19 landslides on Kyushu.

As hot air was being sucked into the storm system, temperatures were rising in many places, including the central city of Kashiwazaki which was hit by a deadly earthquake on July 16.

Slumped-over elderly evacuees fanned themselves in shelters as temperatures hit 40 degrees Celsius (104 degrees Fahrenheit) on Thursday. The mercury also rose past 30 degrees in Kashiwazaki on Friday.

About two weeks ago, three people were killed in Typhoon Man-yi, one of the most powerful typhoons to hit Japan in decades. A fourth person remains unaccounted for.