Financial markets in Taiwan have been closed, along with many businesses and schools, and all domestic flights have been cancelled.
Although the eye of Typhoon Sinlaku is not expected to make landfall, forecasters are predicting that the storm's outer winds would start hitting the northern half of the island by Friday afternoon.
In the early hours of Thursday morning the typhoon passed over Japan's Okinawa islands - causing dozens of injuries, power cuts and damage to homes.
But five Filipino sailors who were missing, feared drowned, were found safe on Friday by Japanese coastguards, according to AFP.
In Taiwan, rescue officials have said that one woman is missing, having been swept away by huge waves at the central coastal city of Hualien, and there was concern for 16 mountaineers who had not returned from a climb.
Financial markets closed
Sinlaku, with a radius of 300 km was located 340 km north-east of Taipei at 1400 (0600 GMT), moving west at 11kph.
In the capital Taipei the streets are unusually empty with many businesses, including the bourse and foreign exchange market, closed.
Many people have been placing sandbag defences around their businesses and homes and been moving furniture and belongings off the ground floor.
Residents have been stocking up on fruit and instant noodles and parking their cars on overpasses, avoiding lower roads that could turn into roaring rivers if there are flash floods.
Most cities in the northern half of the island closed schools and government offices, while airlines cancelled domestic flights.
Counting the costs
The BBC's Helen Leavey in Taipei says that no-one is taking any chances - last year Typhoon Toraji killed about 200 people in central and eastern Taiwan.
Meanwhile South Korean officials have confirmed that 120 people were killed and 64 are still missing after the devastating Typhoon Rusa, which ravaged the Korean peninsula last weekend.
Rusa was the worst typhoon to hit South Korea for 40 years and estimates of the cost of property losses are continuing to escalate as reports of damage come in from remote areas.
The figure has grown to a high of 4.3 trillion won ($3.3bn), about four times the previous record of losses of 1.07 trillion won wrought by Typhoon Olga in 1999.