China has denounced Japan for releasing treated and diluted water into the ocean from the Fukushima Daiichi nuclear power plant at the annual meeting of the International Atomic Energy Agency.

Japan's Science and Technology Policy Minister Takaichi Sanae has hit back. She said China is the only country despite being a member of the IAEA that continues to spread scientifically groundless information and impose unreasonable import restrictions.

The IAEA general conference started on Monday. Representatives of the member states are delivering speeches.

China's representative said that despite strong opposition from related countries, Japan started the water discharge and caused widespread concern in the international community.
And he called the treated water "nuclear contaminated water."

In response to these remarks, Takaichi said the IAEA's review concluded before the release that the treated and diluted water meets international safety standards.

She said the Japanese government has been providing careful, science-based explanations to the international community. She added that many parts of the world understand and support Japan's efforts.

Takaichi said the government will continue ensuring the safety of the operation until the last drop of the water has been discharged into the sea with the continued involvement of the IAEA.

She urged China to act based on science and send out correct information.

Earlier that day, IAEA Director General Rafael Grossi expressed his agency's commitment to ensuring the safe release of treated and diluted water from the Fukushima plant.

Grossi said the IAEA is independently monitoring, and evaluating the situation there.

He said for that purpose the agency has set up a permanent office at the plant. He added that the agency will continue to make sure that no harm will come out of the operation for decades to come.

The Fukushima Daiichi plant suffered a triple meltdown in the 2011 earthquake and tsunami.

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

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