Typhoon Halong, packing winds of up to 198 kilometres per hour, could make landfall in southwest Japan late today or early tomorrow, according to the Japan Meteorological Agency.
The outer bands of the storm have already brought heavy rain and strong winds to large areas of the Japanese archipelago, as television footage showed high waves triggered by the typhoon splashing over breakwaters.
The storm and torrential rains earlier this week have left one dead and four injured, public broadcaster NHK said.
Over the next 24 hours, the storm was expected to dump 70 centimetres of rain on the southwest island of Shikoku, which had already been lashed by downpours from another typhoon last weekend, the national weather agency said.
The agency warned of major landslides and floods mainly in western Japan, while local authorities in Tokushima in Shikoku issued an evacuation advisory to some 44,100 residents, officials said.
The typhoon, which was about 210 kilometres off Shikoku's southern tip at 0930 IST, was moving northeast at 15 kilometres per hour, the agency said.
Last weekend, a man drowned in a raging river while more than half a million people were advised to evacuate as heavy rain from Typhoon Nakri lashed the country.
