Sony's plant in Nagasaki, which resumed full operations on Sunday, is the company's major production facility for image sensors for smartphones, it said.
The company said it had yet to decide when to restart the Kumamoto plant.
"The impact of the Kumamoto plant suspension on Apple is expected to be limited," Hiroyuki Shimizu, principal research analyst at Gartner, said.
Sony has 45 percent of the market for complementary metal-oxide semiconductor image sensors, a type of integrated circuit that converts light into electrical signals, according to research firm Gartner.
Sony shares fell 6.8 percent on Monday.
The earthquakes, which killed at least 42 people, led to shut downs at a number of other manufacturing companies.
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