Japan will reportedly fortify inspection protocols of some fishery products imported from South Korea from next month.

Japan's Sankei Shimbun daily reported on Thursday that the Ministry of Health, Labor and Welfare will make a related announcement on Thursday.

The report said it's very unusual for Tokyo to tighten inspection of fishery imports from a certain country, suggesting the move is a response to Seoul's import ban on some fishery products from Japan.

South Korean halibut and frozen clams are reportedly among the items that will be subject to enhanced inspection procedures.

In April, the World Trade Organization issued a final verdict in favor of Seoul’s import restrictions on some Japanese seafood in the wake of the 2011 Fukushima nuclear disaster.

Tokyo contends the ruling, and has said it will utilize Japan's position as this year’s G20 host to reform the international body.