Typhoon Chaba is churned slowly northeast towards Japan and is threatening further damage to areas battered by a deadly typhoon just over a week ago.
The storm, which has already claimed two lives, is heading for Okinawa and Japan's southernmost main island of Kyushu, with heavy rains predicted to rake a wide swathe of western and central Japan over the weekend.
Two men, one out surfing, were killed in western Japan on Thursday after being swept away by high waves spawned by the storm's approach.
Chaba, which means "hibiscus" in Thai, was around 340 kilometres north northeast of Minamidaito island in Okinawa prefecture as of 3 p.m. (7 a.m. Irish time) and moving northeast at a rate of 10 kilometres an hour.
Winds near the storm's centre were gusting up to around 180 kilometres an hour. Television footage showed huge waves crashing on beaches and breakwaters, but there was still little rain.
The storm's expected course is similar to that of typhoon Megi, which last week set off landslides and flooding that killed 10 people in Japan and at least three in South Korea before heading out to sea late last Friday.