Companies including Sony and TSMC, the world's largest contract chipmaker, have plants in the area of the quake.
A Sony spokesperson said the company was checking the situation.
TSMC did not immediately respond to a request for comment.
The Japanese government issued emergency earthquake warnings on Tuesday for Kumamoto, Nagasaki, Kagoshima, Fukuoka, Saga, Oita, and Miyazaki prefectures, all on Japan's southern Kyushu island.
A tsunami warning for a wave measuring one metre was briefly issued after the earthquake, the Japan Meteorological Agency said.
Japan is one of the world's most earthquake-prone countries, with a tremor occurring at least every five minutes. Located along the "Ring of Fire" of volcanoes and oceanic trenches partly encircling the Pacific Basin, Japan accounts for about 20 per cent of the world's earthquakes of magnitude 6.0 or more.
A massive earthquake in Kumamoto 10 years ago killed 275 people and injured a further 2739, according to an official count.
Kyushu Electric Power said about 40,000 homes had lost power as a result of the quake, while railway company JR Kyushu said it had suspended services, including its high-speed bullet trains.
No irregularities were reported at the nuclear power stations in the area, Japan's nuclear regulation authority said.
