It is "absolutely logical" that Japan's plan to release treated radioactive water from its Fukushima nuclear plant is attracting great interest in the region, the head of the International Atomic Energy Agency (IAEA), Rafael Grossi, said on Sunday.

Grossi also said he understands concerns remain over the plan but added that a review by the IAEA released last week found it was "in conformity with international safety standards" if executed according to plan.

Grossi met with South Korea's opposition Democratic Party members on Sunday who expressed strong public concerns over Japan's plan and criticized the IAEA's findings.