A powerful typhoon headed toward southern Japan Sunday, with officials warning of record rainfall and winds strong enough to snap power poles and flip vehicles.

Typhoon Haishen, categorised as "large" and "extremely strong", was expected to move in the afternoon through the Amami region of small islands near Kyushu that separate the Pacific Ocean and the East China Sea.

At noon (0300 GMT), Haishen was about 80 kilometres (50 miles) east of Amami Oshima island, with gusts up to 234 km (145 miles) per hour.

The storm was forecast to head north-northwest and travel off the western coast of Kyushu -- one of Japan's main islands -- from the evening through early Monday before reaching South Korea, according to the Japan Meteorological Agency.

Once the storm comes near inhabited islands, its violent winds might become strong enough to snap power poles and flip vehicles, meteorologists have warned.

The government of Prime Minister Shinzo Abe was scheduled to hold a special cabinet meeting later Sunday to discuss ways to deal with the approaching typhoon.

The weather agency said it was not likely to issue its most serious typhoon warning, but asked residents to still exercise their "most serious caution" for possible record rain, violent winds, extreme waves and surging tides.

"In areas where the typhoon will draw close, record-level rainfall is expected. It may cause landslides or it could cause even large rivers to flood," Yoshihisa Nakamoto, director of the forecast division at the weather agency, said during a televised briefing.

He added that surging tides may cause widespread flooding in low-lying areas, particularly around river mouths.

- Blackouts, cancelled flights -
Hundreds of thousands of residents of Kyushu have been advised to seek safety at shelters, including all of 250,000 residents of Kagoshima city and 36,600 residents of Goto City of Nagasaki, which the typhoon may hit directly.

Rather than seeking shelters at designated local schools and community centres, some residents have chosen to seek safety at local hotels to try and reduce the risk of coronavirus infections at crowded public shelters, according to local media.

Local governments also suggested affected residents to think of ways to avoid crowded public shelters if possible.

The storm has forced the cancellation of nearly 550 flights, according to national broadcaster NHK.

In Kagoshima, 21,360 households have lost power, while 3,560 other households on Okinawa also experienced power outages, according to local utilities.

Toyota said it would suspend operations at three plants in Kyushu until Monday evening, while other companies, including Canon and Mitsubishi Electric, reportedly planned to take similar measures.

Haishen also forced the Japanese coast guard to suspend its search for dozens of missing sailors from a cargo ship that sank in a separate storm, after two crew members were rescued.

The Gulf Livestock 1, carrying 6,000 cows and 43 crew, issued a distress call Wednesday near Amami Oshima as Typhoon Maysak passed through the area.

But patrol ships have remained in the sea so that the search can resume after Haishen leaves the region, a duty officer told AFP.