The head of the International Atomic Energy Agency says it will continue onsite monitoring to ensure the safe release of treated and diluted water from the crippled Fukushima Daiichi nuclear power plant into the sea.

The UN agency's Director General Rafael Grossi made the remark on Wednesday at a meeting in Iwaki City, Fukushima Prefecture, attended by heads of local municipalities and fisheries cooperatives.

The plant's operator, Tokyo Electric Power Company, told the participants that the IAEA's report released the day before said Japan's treated water release plan is consistent with international safety standards.

Iwaki Mayor Uchida Hiroyuki said that despite the report's assessment, safety and a sense of security are not the same. He requested further explanation, saying local residents and those in the fishing industry are not yet convinced.

Grossi joined the session after Uchida's remarks. He referred to the IAEA's decision to open a permanent office at the plant to monitor the water release.

Speaking about people's doubts and concerns, he said he does not have "a magic wand." But he added, "We are going to stay here with you for decades to come, until the last drop of the water which is accumulated around the reactor has been safely discharged."

Water used to cool molten nuclear fuel at the plant has been building up. It mixes with rain and groundwater and is treated to remove most radioactive materials, but some tritium remains.

The government plans to release the treated water around this summer after diluting it to reduce the tritium concentration to about one-seventh of the World Health Organization's safety standards for drinking water.