China will carry out sweeping reforms to the structure of its military, state media reported, in moves intended to enhance the ruling Communist Party's control over the People's Liberation Army.

China's armed forces have long been plagued by inefficiency and corruption, even as Beijing adopts more assertive stances in territorial disputes with neighbours including Japan and the Philippines over islands in the East and South China Seas.

President Xi Jinping's widely-publicised anti-corruption campaign -- which critics say has been used for factional infighting -- has ensnared former top generals Guo Boxiong and the late Xu Caihou among a long list of high-ranking military officers.

Xi told a three-day meeting of more than 200 senior government officials and military brass: "The ultimate leadership and command power of the military must be better centralised under the party and the Central Military Commission (CMC)."

The PLA is technically the armed wing of the Communist Party, rather than the Chinese state, and the official Xinhua news agency cited Xi as saying: "Under the leadership of the Party, the army has gone from small to large, from weak to strong, and from victory to victory."

The military's four powerful headquarters -- general staff, political, logistics and armaments -- will be "reorganised" under the CMC, Xinhua reported after the closed-door meeting ended Thursday.

New "battle zones" will be created to focus on combat and joint operation command systems will be set up, it cited Xi as saying, replacing China's existing seven "military regions", which have separate command structures and significant administrative responsibilities.

A new military discipline department and an audit office will be established as part of efforts to "get rid of the soil in which corruption can arise and grow", Xinhua said.

Xi re-iterated a September announcement that the military's numbers will be cut by 300,000 personnel, but said that China was changing "from a large country to a large and powerful one".

China's neighbours have expressed concerns over its actions, particularly its rapid construction of artificial islands in disputed South China Sea waters.

The defence ministry in Beijing on Friday said the government's defence policy will remain "defensive in nature".

"Chinese armed forces will always be a staunch force to safeguard world peace and regional stability," Xinhua quoted ministry spokesman Yang Yujun as saying.