The quake hit around 100 kilometres (60 miles) off the island of Pinghu in the Taiwan Strait, at a depth of 13 km at 7:57 am (2357 GMT Sunday).
There were no immediate reports of casualties or damage. There were local media reports of people running outside after the quake was felt in the city of Magong on Pinghu island.
Taiwan's central weather bureau measured the quake at 6.1 magnitude.
The Hong Kong Observatory said it had received reports that tremors were felt by residents. The epicentre was 470 km northeast of the city, it added.
Taiwan island lies near the junction of two tectonic plates and is regularly hit by earthquakes.
In February, its eastern Hualien city was hit by a 6.4-magnitude earthquake which killed 17 people.
The island's worst such disaster in recent decades was a 7.6-magnitude quake in September 1999 that killed around 2,400 people.
Published : November 26, 2018
By : Agence France-Presse Taipei