China has denounced Japan's plans to boost military purchases, accusing it of playing up regional tensions as an "excuse" to ramp up defence spending.

The cabinet of hawkish Japanese Prime Minister Shinzo Abe agreed Tuesday to spend 24.7 trillion yen ($240 billion) between 2014 and 2019 -- a five percent boost to the military budget over five years.

Japan plans to purchase stealth fighters, drones and submarines as part of its efforts to boost military hardware that will beef up defence of far-flung islands amid a simmering territorial row with China.

China is "firmly opposed" to Japan's spending plans, defence ministry spokesman Geng Yansheng said in a statement released late Friday.

He accused Tokyo of playing up the perceived military threat from China as an "excuse" to expand its military.

Japan's actions "must cause great concern to neighbouring countries in Asia and the international community", Geng said.

Tensions between Beijing and Tokyo have flared over the last year as the two have engaged in a bitter war of words over uninhabited islands in the East China Sea, known as Diaoyu in China and Senkaku in Japan.

China has sent ships and aircraft into the area on scores of occasions, prompting counter deployments by Japan.

Tensions were ratcheted up last month when China abruptly declared a new Air Defence Identification Zone over the East China Sea, including over disputed Tokyo-controlled islands called Senkaku in Japanese and Diaoyu in Chinese.

The simmering tensions have hammered diplomatic ties. Abe has not held direct talks with Chinese President Xi Jinping since sweeping elections late last year.

China has been boosting its defence budget for decades, and last year was the world's second biggest military spender with an outlay of $166 billion, according to Sweden-based think-tank the Stockholm International Peace Research Institute (SIPRI).

United States spent $682 billion on its military in 2012, while Japan spent $59 billion, SIPRI said.