The head of US Army Pacific has warned that the Chinese military is on an "irresponsible path" in its growth across the region.

General Charles Flynn told a news conference in Tokyo on Wednesday he was concerned by China's "incremental" and "insidious" military capabilities.

He cited a series of recent injuries to crew members of Philippine ships caused by water cannons fired by the Chinese coast guard in and around the disputed areas in the South China Sea.

Flynn said China's aggressive conduct across the region was "illustrative" of its "irresponsible behavior."

The commander said he intends to "prevent that irresponsible behavior from expanding" by strengthening ties with allies such as Japan, the Philippines and Australia through joint training and exercises.