TOKYO: China is considering declaring a new Air Defence Identification Zone (ADIZ) over the South China Sea, according to a Japanese report Friday, a move likely to fan tensions in an area driven by territorial disputes.

The report comes months after Beijing caused consternation with the sudden declaration of an ADIZ above the East China Sea, covering islands at the centre of a sovereignty row with Tokyo.

It also comes as countries in the region grow increasingly concerned about what they see as China's aggressive territorial claims.

Working level officials in the Chinese air force have drafted proposals for the new zone, which could set the Paracel islands at its core and spread over much of the sea, the Asahi Shimbun said, citing unnamed sources, including from the Chinese government.

The draft was submitted to senior Chinese military officials by May last year, the respected daily said.

Beijing claims the South China Sea almost in its entirety, even areas a long way from its shoreline.

The countries surrounding the sea have competing and overlapping claims to the area and are in dispute with Beijing, including over the ownership of islands.

Many countries, including the US and Japan, use ADIZs as a form of early warning, allowing them to track aircraft approaching their airspace.

Planes entering the area are frequently asked to identify themselves and to maintain radio contact with local authorities.

Any aircraft causing concern can trigger the launch of fighter jets, which are scrambled to intercept it.

The draft says the zone would at a minimum cover the Paracels, and could go as wide as the majority of South China Sea, the Asahi said.

Beijing is still deliberating the extent of the zone and considering the timing of an announcement, the paper said.

Japan, South Korea and others reacted with anger in November when Beijing unilaterally declared an ADIZ in the East China Sea.

China demanded all aircraft provide flight plans when traversing the area, give their nationality and maintain two-way radio communication, or face “emergency defensive measures”.

The US said it would not comply, and, in what was seen as a challenge to Beijing, promptly flew military planes through it.

The zone covers disputed Tokyo-controlled islands — known as the Senkakus in Japan and the Diaoyus in China — where ships and aircraft from the two countries already shadow each other.

Its sudden declaration bolstered claims that China is throwing its growing military weight around.

Observers say the establishment of a similar zone in the South China Sea is a likely move for Beijing.

In November the southern Chinese island province of Hainan passed a rule requiring foreign fishing vessels to obtain permission to enter its waters, which it defined as the bulk of the sea.

In December, US Secretary of State John Kerry warned China against any move to declare an air defence zone over the sea, which is a vital transport route through which much regional and global trade passes.