Thousands of residents are already in shelters and the country's meteorological institute JMA has issued a "special warning", something that is done extremely rarely.

- Maximum vigilance is required, said Ryuta Kurora, head of the JMA's forecasting unit on Saturday.

- The wind will be so strong that some houses may collapse, said Ryuta Kurora, who also warned of floods and landslides.

So far, 2.9 million residents of Kyushu have been told to evacuate, according to authorities, and in Kagoshima, more than 8,500 people were said to be already in local shelters as of Sunday morning.

Over 25,000 households in Kagoshima and neighboring Miyazaki in southern Japan were simultaneously without electricity due to the storm.

"Getting stronger"

However, evacuation is not mandatory and in previous extreme weather events authorities have struggled to convince residents to take shelter quickly enough.

A government official in Kagoshima prefecture says so far no damage to people or buildings has been reported, but conditions are rapidly deteriorating.

- The rain and wind are getting stronger.

The rain is so heavy that you can't really see what's out there.

It looks completely white, he says.

Satellite imagery taken on Saturday shows storm Nanmadol south of Japan, near the country's smaller islands.

To the left are Taiwan and the east coast of China.

Photo: Japan Meteorological Agency/AFP/TT

The storm Nanmadol, a so-called typhoon or intense tropical cyclone, moves in over Japan on Sunday and will not reach the country's main island until Wednesday.

Japan's typhoon season is currently underway, and the country is hit by about 20 such storms a year.

The country is repeatedly hit by heavy rains that cause landslides or floods.