Footage shows buildings at precarious angles in the city of Hualien , near the quake's epicentre.
Sky News Asia Correspondent Stas Butler says the quake struck just before 8am local time.
He says in the hours since -- there's been more than 30 aftershocks.
The quake triggered tsunami alerts for southern Japan and the Phillippines.
Japanese authorities reported several small waves reaching its southern islands --before downgrading it's warning.
There's 137 New Zealanders registered in Taiwan, and 428 in Japan.
