Japan scrambled fighter jets on Saturday to head off a Chinese state-owned plane that flew near the disputed Diaoyu islands, which Japan calls the Senkakus, a Japanese Defence Ministry spokesman said.
Japanese jets were mobilised after a Chinese maritime aircraft ventured 120 kilometres north of islands at about noon, the spokesman said.
The Chinese Y-12 twin-turboprop later left the zone without entering Japanese airspace, he added.
It was the first time Japanese fighters had been scrambled this year to counter Chinese aircraft approaching the islands, the spokesman said.
Japan dispatched eight F-15 fighter jets to the area on December 13 after its coast guard spotted a Chinese marine surveillance plane near the isles, with its foreign ministry describing the flight as a "further dangerous act" that "escalates the situation". China protested a day later that Japanese military planes entered its airspace near the islands.
The dispute over control of the islands in the East China Sea has strained relations between Asia's two biggest economies and stoked fears of an arms build-up in the region. Japan's new prime minister, Shinzo Abe, vowed in his New Year message to "defend our land, airspace and territorial waters".
Abe also held meetings with officials on Saturday to discuss how to intercept Chinese planes near the disputed islands, ribenxinwen.com  reported yesterday.
The latest crisis in the longstanding dispute was triggered by the Japanese government's purchase in September of three of the disputed islands from their private Japanese owner.
China last month filed a report with the United Nations detailing grounds for its sovereignty claims over the islands in an area rich in oil, gas and fish.
Additional reporting by staff reporter