Taiwan's government said on Wednesday that 711 people had been injured after a a 7.2 magnitude earthquake which struck earlier in the day, and that 77 people were trapped.
Shortly after, Taiwan's National Fire Agency said the number of deaths had risen to seven.
People are reportedly trapped under buildings and in tunnels after Taiwan's strongest quake in 25 years.
The quake that hit Taiwan was M7.2 but the Japan Meteorological Agency upgraded the quake that hit Japan magnitude to 7.7.
Military personnel were dispatched to help with disaster relief and schools and workplaces suspended operations as aftershocks hit Taiwan, CNN reported.
The Ministry of Foreign Affairs and Trade said there were 137 New Zealanders registered with it in Taiwan and 428 in Japan.
It said Kiwis in areas affected in Taiwan and Japan should follow the advice of local authorities.
Look back at how the day unfolded here:
Japan was rocked by its deadliest quake in eight years on New Year's Day when a 7.6 magnitude temblor struck in Ishikawa prefecture, on the western coast. More than 230 people died in the quake that left 44,000 homes fully or partially destroyed.
Earthquakes are common in Japan, one of the world's most seismically active areas. Japan accounts for about one-fifth of the world's earthquakes of magnitude 6 or greater.
On March 11, 2011, the northeast coast was struck by a magnitude 9 earthquake, the strongest quake in Japan on record, and a massive tsunami. Those events triggered the world's worst nuclear crisis since Chernobyl a quarter of a century earlier.
