The report was based on a review mission carried out in October by the IAEA's task force comprising the agency's officials and independent experts from 11 countries including China, which currently imposes an import ban on Japanese marine products.

The task force reviewed facilities and equipment to discharge the water, treated with the liquid processing system that removes most radionuclides except tritium, and held talks with officials of the plant operator Tokyo Electric Power Company Holdings (Tepco), the Nuclear Regulation Authority and the Japanese government.

Japan has so far discharged a total of 23,400 metric tons of water since August last year. Tepco plans to begin the release of final batch for fiscal 2023 in late February.

The standards constitute global reference for protecting the public and the environment from harmful effects of ionizing radiation, and the latest report reaffirmed the conclusions from the agency's comprehensive safety report issued in July last year prior to the beginning of the discharge.

The Japanese government sees the disposal of the wastewater — generated in the process of cooling melted reactor fuel and mixed with rain and groundwater — as a key step in decommissioning the Fukushima No. 1 power plant that suffered nuclear meltdowns triggered by the 2011 earthquake and tsunami disaster.