Taiwan authorities on Friday issued a sea warning for the island's second typhoon of the year, which was expected to bring heavy rain and wind gusts of up to 108 kph (67 mph) before moving on to China.
Typhoon Molave, centred 360 km (223 miles) southeast of Taiwan at 0300 GMT, was expected to brush the island by late Friday with sustained winds up to 83 kph (52 mph), the Central Weather Bureau said.
"The storm has already constituted a threat in the southern Taiwan Strait," the bureau said on its website. "Boats should make extra preparations."
Molave, which takes its name from a tree native to the Philippines, will move toward the southeast coast of China on Saturday, said forecasting website Tropical Storm Risk.
Typhoons regularly hit China, Taiwan, the Philippines and Japan in the second half of the year, gathering strength from the warm waters of the Pacific Ocean or South China Sea before weakening over land.
Two major typhoons reached Taiwan last year, including a slow-moving storm that brought more than 1,100 mm (43 inches) of rain and killed 12 people.