Taiwan is bracing itself for the arrival of a vast typhoon, expected to hit the island in the next day.

Thousands of tourists have been evacuated from offshore islands ahead of category five Typhoon Nepartak.

The super typhoon packed winds of up to 263km (163 miles) an hour, some 780km south-east of Taiwan's Hualien city on Wednesday, officials said.

They also warned of the risk of flooding and mudslides as high winds and lashing rains were expected.

"As the typhoon kept gaining strength and approaching Taiwan over the past three hours, the Central Weather Bureau decided to issue a sea warning at 14:30 local time (06:30 GMT)", senior forecaster Chen Yi-liang told AFP.

"Residents must heighten their vigilance."

Fishermen rest after tying their boats at the northeast fishing port in Yilan, Taiwan on July 7, 2016. Photo: Reuters

Around 3,000 tourists have been evacuated from the Green and Orchid Islands, two popular tourists spots off south-eastern Taitung county, said local government officials.

A storm is classed as a super typhoon if it reaches maximum sustained 1-minute surface winds of at least 65 m/s (145mph), the equivalent of a category-five hurricane in the Atlantic basin.

Some 35,000 soldiers have been put on standby, according to the defence ministry.

Transport Minister Hochen Tan also assured citizens that measures have been taken to ensure Taoyuan Airport will not be flooded.

Taiwan is often hit by typhoons, with super typhoon Dujuan killing three people and leaving more than 300 injured in Taiwan in 2015.

In the same year, Typhoon Soudelor killed at least eight people in Taiwan and 21 in China.

The island's rugged terrain, with mountains up to 4,000 metres (13,000 ft) stretching across the territory, increases the risk of flooding and landslides during a typhoon.