The action was "necessary to safeguard national sovereignty, the country's security and maintain peaceful development" Efe news quoted People's Liberation Army Air Force spokesman Shen Jinke as saying to the Global Times on Monday.
Eight military aircraft -- at least two of them fighter planes -- on Sunday flew over the the Miyako Strait close to the southern island, the Japanese Ministry of Defence confirmed to Efe news.
The strait lies between Miyako and Okinawa islands in the East China Sea, a site of tense territorial dispute between Japan and China over the Senkaku islands.
The planes were taking part in a manoeuvre conducted between the East China Sea and the West Pacific, and it included a total of around 40 planes, Shen confirmed.
The exercises included vigilance, attack and air fuelling to test the forces' capabilities, he added.
H-6K bombers, Su-30 fighters and tankers participated in the manoeuvre and will regularly be flying over the Miyako Strait, according to the spokesman.
Shen said the Chinese planes first flew over the region in 2015.
However, the Japanese ministry said it was the first time that Chinese warplanes passed through the area.
The Chinese aircraft, which apparently comprised four H-6K bombers, two surveillance aircraft and two fighters, did not infringe on the Japanese territorial airspace, the ministry noted.
The sovereignty dispute over Senkaku islands, administered by Tokyo, has intensified since Japan nationalised several uninhabited islets in 2012. The tension in the area also has increased following the growing military deployment by both the countries.
