A Chinese Foreign Ministry spokesman said on Tuesday that China does not accept Japan's protest and representation over Chinese maritime surveillance ships' patrol in waters off the Diaoyu Islands.

Hong Lei made the remarks at a press conference in Beijing when commenting on Japan's latest representation earlier on Tuesday.

"The Diaoyu Islands and their affiliated islets have always been China's inherent territory. The patrol conducted by China's maritime surveillance ships in waters off the islands is a normal performance of duty to exercise jurisdiction," Hong said.

He added that as Japan had sent vessels and planes several times to "illegally enter the waters and airspace of the Diaoyu Islands," China had lodged protest and representation to the Japanese side to demand an end to its illegal activities.

According to media reports, the Japanese side earlier on Tuesday summoned Chinese Ambassador to Tokyo Cheng Yonghua over the patrol of four Chinese maritime surveillance ships in waters off the Diaoyu Islands.