Footage from Kumamoto captures the moment a powerful earthquake struck southwestern Japan, sending newsroom staff diving under desks as computer monitors and hanging signs shake violently.

A magnitude 7.1 earthquake hit the Kumamoto area on Japan's southern island of Kyushu late on Tuesday, leaving at least 13 people dead and many others injured or missing.

Japan's Prime Minister Sanae Takaichi said rescue operations continued overnight, calling it "a race against time" to reach those still trapped.

More than 260,000 residents were advised to evacuate across Kumamoto and neighbouring Nagasaki prefectures.

At the Yatsushiro factory, a collapsed chimney buried workers beneath rubble, while officials said several people were still unaccounted for on Wednesday morning.