Decisive blow

"This action once again puts fishermen and victims of the nuclear disaster in dire straits. This will deal a decisive blow to Fukushima's fishing industry, and consumers will likely exercise justified caution by refraining from purchasing," they said.

Speaking of Japan's insistence on selecting the ocean discharge plan from several options, Zhang Yulai, vice-president of the Japan Institute of Nankai University, said that because of Japan's history as an island country, "a strong sense of crisis often outweighs moral principles and becomes the standard for government decisions".

Despite strong opposition, the government's decision is "primarily driven by factors, including cost considerations and vested interests between the government and TEPCO", Zhang said.

Environmental and civic groups rallied across South Korea on Thursday, including Seoul, the port city of Busan and the southern island of Jeju, calling for withdrawal of Japan's discharge plan.

South Korea's Prime Minister Han Duck-soo said on Thursday the import ban on fisheries and food products from the Fukushima region will remain in place until the concerns are eased, Yonhap News Agency reported.

Since 2013, South Korea has banned imports of all fishery products from eight Japanese prefectures near Fukushima because of concerns over radiation levels.

All seafood imported will be thoroughly tested for radioactivity, Han said in a statement.

Japan should strictly comply with scientific standards and be transparent in providing information as promised to the international community, Han said.

South Korea's main opposition Democratic Party of Korea proposed bills, including enhancing regulations on place-of-origin labeling, while seeking to designate damage from the water discharge as a disaster and lay the legal groundwork for seeking indemnity from Japan.

Li Ruoyu, a visiting research fellow at the Institute of Japanese and Korean Studies at Sichuan Normal University, said if problems do arise, the first victims will be the Japanese citizens.

"Should unforeseen circumstances occur, the Japanese government will still make efforts to remedy the situation. The problem, however, is that any remedial measures will inevitably be reactive," Li said.

"There will be evaluations after the ocean dumping of nuclear-contaminated water. However, arriving at scientific conclusions takes time, and no remedial measures can undo the damage already caused," he said.