The Fukushima nuclear plant was wrecked by a tsunami in 2011.
Authorities in China have vowed to take "all necessary actions", including extending a ban on seafood from 10 prefectures of Japan, including Fukushima and capital Tokyo, after Tokyo begins releasing treated radioactive water from nuclear plant into the sea, according to South China Morning post (SCMP). The United Nations nuclear watchdog this week gave Japan the greenlight to begin discharging more than a million metric tons of water, enough to fill 500 Olympic swimming pools, used to cool the plant's fuel rods after it was wrecked by a 2011 tsunami.
There are concerns on residual nuclear contamination in China.
Quoting the General Administration of Customs, SCMP said that the plan to discharge the water from the 2011 nuclear disaster "failed to fully reflect expert opinions" and that it will take "all necessary measures" to ensure the safety of Chinese consumers.
"Since the Fukushima nuclear disaster in 2011, China's customs have attached great importance to the issue of radioactive contamination of Japanese food imported to China. It has closely monitored the relevant measures taken by the Japanese government, continued to assess the risk and responded promptly," the customs agency said on Friday.
Seafood, such as scallops, and Japanese sake are widely popular in the Chinese market.
It was the biggest buyer of Japanese seafood exports last year, even though it is among several countries that restrict imports from some Japanese regions because of the nuclear accident.
China is also the fiercest critic of Japan's planned release of the water saying it threatens marine life and human health.
China has not said what action it will take if the release goes head but it has warned Japan that it must "bear all the consequences" of its action. The release is due to start in coming weeks and take up to 40 years.