South Korean media have reported on the visit by experts from the country to the crippled Fukushima Daiichi nuclear power plant to assess Japan's plan to release treated and diluted water from the plant into the ocean.

The South Korean team wrapped up its two-day visit to the plant on Wednesday.

Rain and groundwater have been seeping into damaged reactor buildings, mixing with water used to cool molten nuclear fuel. That water is treated to remove most of the radioactive materials in it. But the filtered water still contains tritium. Japan plans to release treated water after diluting it to reduce tritium levels to one-seventh of the World Health Organization's safety standards for drinking water.

South Korea's Yonhap News Agency quoted the head of the team, Yoo Guk-hee, as saying the team will likely be able to "make progress" in terms of checking the safety of the water.

Yoo also reportedly said, "We need to engage in additional analysis" of the function and role of facilities in the plant. Yonhap reported Yoo did not mention whether the team's findings were sufficient to reach a conclusion.

In a news program aired by South Korea's public broadcaster KBS, a correspondent in Fukushima Prefecture said Wednesday's visit lasted more than eight hours, but that there were limits to the examination as it was carried out with briefings by the Japanese side.

The correspondent added that there will be a question-and-answer session with the plant's operator and others on Thursday to make up for that perceived shortcoming with the visit.

A commentator in the studio said if the release is decided, it will continue for 30 years, and that it is therefore important to continue checking the discharge carefully.