Japan has proposed to China setting up a dialogue involving nuclear experts from both countries to discuss Tokyo's plan to release treated radioactive water from the crippled Fukushima No. 1 nuclear complex into the sea, government sources said Wednesday.

China, which remains opposed to the plan, has yet to respond to the call for a working-level consultation, the sources said. Japan, which had received reassurance from the International Atomic Energy Agency over the plan's safety, aims to start the water release around this summer.

Tokyo and Beijing have been at odds over the planned discharge of water, which has gone through a process to remove most of the radionuclides, except tritium, into the Pacific Ocean from the Fukushima plant, wrecked by a devastating earthquake and ensuing tsunami in March 2011.