Japan's continuous meddling in the South China Sea is a "clumsy show" that goes against not only the interests of the G7, but also the peace and security of the South China Sea region, a Foreign Ministry official said on Wednesday.

Foreign Ministry spokeswoman Hua Chunying made the remarks in a news conference after reports that Japanese Prime Minister Shinzo Abe is expected to bring up the South China Sea issue when meeting with United States President Barack Obama in Japan on Wednesday.

It's also reported that the G7 summit declaration will include the "three principles of rule of law" on solving maritime territorial disputes, which Abe brought up in 2014.

Hua described moves by Japan as "petty shrewdness" by taking advantage of its status as the host of the G7, while the summit should focus on global economic governance and cooperation.

Hua reiterated that China's activities in the South China Sea are totally justified and lawful, and the country has the right to, and must, guard its legitimate interests.

"For some time, Japan has kept hyping the South China Sea issue, sparing no effort to stir up trouble everywhere… It's just another clumsy show by Japan. I believe everybody has a clear-headed understanding of it," Hua said.