A Chinese Foreign Ministry spokesperson has reiterated his country's opposition to Japan's plan to release treated and diluted water from the crippled Fukushima Daiichi nuclear power plant into the ocean.

Wang Wenbin told reporters during a regular briefing on Wednesday that China urges Japan to cancel the plan and to address its neighboring countries' concerns in a sincere matter.

He said if Japan acts arbitrarily, it would have to bear a historical responsibility.

A reporter pointed out, quoting Japanese media, that the amount of tritium, a type of radioactive substance, in the wastewater released by Chinese nuclear plants in 2021 exceeded the maximum level of tritium in the treated water to be discharged by Japan.

Wang responded, emphasizing that "Fukushima's nuclear contaminated water" has gone through a nuclear meltdown which is different from the usual release from nuclear plants.