The State Administration for Market Regulation, China's market regulator, said it would urge food producers and operators to stop purchasing and using aquatic products from Japan.
The move came as Japan started the release of nuclear-contaminated water into the Pacific Ocean despite widespread opposition on Thursday, which the regulator dubbed "extremely selfish and irresponsible."
Food producers and operators are strictly prohibited from purchasing and using aquatic products from Japan, to process food, make meals or sell them both online and offline, the SAMR said.
The market regulator will take harsh steps again those breaking the rules, and will continue to strengthen sampling and monitoring of imported aquatic products in the market, it added.