Whether China sets up air defense identification zones depends on the extent of threats it faces from the skies, a Defense Ministry spokesman said on Thursday.

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"As a sovereign country, China, is entitled to establish ADIZs," Yang Yujun said.

Yang was responding to a question about a report from Japan's Asahi Shimbun that China has drafted proposals for an ADIZ over the South China Sea.

Yang said at the monthly news briefing that many factors have to be considered in deciding whether to establish an ADIZ.

An ADIZ is neither sovereign airspace nor a no-fly zone, he said. Establishing an ADIZ does not necessarily mean a change of territorial land, sea and airspace.

"What is noteworthy is that China has confidence in the stability of the broad situation in the South China Sea and China's relations with countries surrounding the sea.

"Also noteworthy is 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 ulterior motive is to distract international attention," Yang said.

In 2013, China established its first ADIZ, which covers part of the East China Sea, including its Diaoyu Islands. The move came 44 years after Japan announced its own ADIZ.

Beijing requires foreign planes to notify the Chinese government of flights through the zone. It promised the zone does not target normal flights by international airliners.

Establishing an ADIZ in the South China Sea is by no means a given, experts said.