China is accusing Japan of using its national security as a pretext for military expansion.
China’s Defense Ministry spokesman Geng Yansheng said in a statement that the move would increase regional tensions, state news agency Xinhua reported.
Earlier this week, Japan said it would buy advanced equipment including drones and amphibious vehicles.
It comes as Tokyo is embroiled in a bitter row with Beijing over islands in the East China Sea that both claim.
“China is firmly opposed to Japan’s relevant actions,” said Geng Yansheng.
The statement said Japan’s security policy caused “great concerns” among neighboring countries.
The announcement of more Japanese military spending came weeks after China established an air defense identification zone over a swathe of the East China Sea, including islands controlled by Japan.
Japan’s PM Shinzo Abe says he wants his country to broaden the scope of activities performed by the military – something currently tightly controlled by the post-war constitution.
Over the five years, Japan plans to buy anti-missile destroyers, submarines, 52 amphibious vehicles, surveillance drones, US fighter planes and 17 Boeing Osprey aircraft, capable of vertical take-off.
According to the Stockholm International Peace Research Institute, Japan ranks fifth in the world for military spending while China is in second place behind the US.