Foreign Minister Yohei Kono said Friday that China should give Japan about six months notice before conducting maritime research in Japan's exclusive economic waters.
Kono told a press conference that Japan is considering a request for notification not of a day or two but rather about six months.
In late August, Kono and Chinese Foreign Minister Tang Jiaxuan agreed in Beijing to set up a mutual notification mechanism to try to resolve disputes over the research activities.
The mechanism will involve the foreign ministers giving each other advance notice of any such activities, according to Japanese officials.
Kono expressed regret about a Chinese marine research ship spotted operating Tuesday through Thursday off Amami-Oshima Island.
He said Japan will protest the incident to China via a high-ranking official.
Meanwhile, Yoshiaki Harada, a lawmaker from the Liberal Democratic Party, told reporters in Beijing he met Friday with Chinese Vice Foreign Minister Yang Wenchang and protested the Chinese vessel's activities.
Yang said the incident was accidental and expressed his regret, Harada said. Yang was quoted as saying that China is willing to work out a mechanism for prior notification.