The head of the International Atomic Energy Agency is due to inspect the disabled Fukushima Daiichi nuclear power plant on Wednesday during his visit to Japan.

Director General Rafael Mariano Grossi is making a three-day trip to the country at the invitation of the Japanese Foreign Ministry. He is expected to meet with Chief Cabinet Secretary Hayashi Yoshimasa on Tuesday, the first day of the visit.

Grossi came to Japan last July. This will be his first visit since the operator of the Fukushima Daiichi plant began releasing treated and diluted water into the ocean last August.

Grossi will examine how the discharge operation is being carried out when he goes to the plant on Wednesday.

Water used to cool molten fuel at the damaged plant has been mixing with rain and groundwater. The accumulated water is being treated to remove most radioactive substances, but it still contains tritium.

Before releasing the treated water into the ocean, the plant's operator dilutes it to reduce the tritium levels to about one-seventh of the World Health Organization's guidance level for drinking water.

The IAEA reaffirmed in a report issued in January that the operation is consistent with international safety standards.

But China suspended imports of Japanese marine products after the operator started discharging the treated and diluted water.

On Monday, Japan marked the 13th anniversary of the accident at the Fukushima Daiichi plant. On that day Japanese Prime Minister Kishida Fumio said that restrictions ungrounded in science must not be tolerated. He vowed to continue to demand that China lift the measure immediately.

The Japanese government hopes to dispel safety concerns at home and abroad with the IAEA's involvement.