Efforts to schedule visits by ruling bloc executives to China are hitting choppy waters, likely due to Tokyo's plan to release treated wastewater from the Fukushima No. 1 nuclear power plant into the sea.

Natsuo Yamaguchi, leader of Komeito, the junior party in Japan's ruling coalition, planned to visit China from Saturday, but the trip was canceled at the last minute by the Chinese side.

Beijing's opposition to the water discharge may be "a major factor" behind the problem, a senior official with the Liberal Democratic Party, Komeito's coalition partner, said.