China on Thursday slashed Japan for cooking up that China will establish an Air Defense Identification Zone (ADIZ) over the South China Sea and said the speculation has ulterior motives.

"It is noteworthy that Japan's right-wing forces have made repeated allegations that China will soon set up an ADIZ over the South China Sea and their purpose is to distract the international attention," Defense Ministry spokesman Yang Yujun said, "the move has ulterior motives."

Speaking at a regular news briefing, Yang noted that an ADIZ is neither territorial airspace nor a no-fly zone. Establishing an ADIZ doesn't mean a change of territorial land, sea and airspace.

"As a sovereign country, China can legitimately establish ADIZs, depending on the extent of threat it faces from the air," Yang said.

He stressed that China has confidence in its relations with countries around the South China Sea and the generally stable situation in the region.

The Asahi Shimbun daily of Japan reported last month that China has drafted proposals for the Air Defense Identification Zone over the South China Sea.