Prime Minister Shinzo Abe has told Japanese troops that Japan would not tolerate the use of force to change the region's status quo, comments likely to rile Beijing which is locked in a long and bitter territorial dispute with Tokyo.

"Use of force for changing the status quo" is an expression often used by Japanese politicians and security experts to indirectly refer to what they see as China's aggressive maritime expansion in the East China Sea and the South China Sea.

Mr Abe's remarks are the second in as many days in which he has effectively said Japan is ready to be more assertive towards China.

Chinese military aircraft flew near Japan for a third day in a row, prompting Tokyo to scramble fighter jets each time.

Mr Abe is seen as a hawkish nationalist who wishes to revise a post-war pacifist constitution drafted by the US and strengthen Japan's defence posture.

His comment comes after the Chinese Defence Ministry warned Japan not to underestimate China's resolve to take measures necessary to protect itself.

Ties between Asia's two largest economies deteriorated sharply after Japan bought three of the disputed East China Sea islets, called the Senkaku in Japan and Diaoyu in China, from a private owner in September 2012, sparking large protests and boycotts of Japanese goods across China.

Patrol ships from both countries have been shadowing each other near the islets, raising fears that an accidental collision or other unintended incident could develop into a larger clash.

Mr Abe said Japanese troops should discard the notion all they should do in peace time was train, calling on them to contribute to peace and stability. "It is your responsibility to resolutely defend the people's lives and property as well as our territory, waters and airspace, and to contribute to the world's peace and stability," Mr Abe said.

Japan scrambled fighter jets after two Chinese bombers and two airborne early warning planes flew near Japan's southern islands into the Pacific and then back into the East China Sea. No violation of Japanese airspace took place.