Authorities in the eastern Chinese province of Zhejiang have seized food items from Japan that were being sold by a local company, Chinese media reported, after Beijing tightened controls on Japanese food imports in response to Tokyo's plan to begin releasing treated radioactive water into the ocean.

The authorities in Jiashan County, located in the province, took away candy and chocolate, as well as beverages produced in Fukushima and two other prefectures on Monday. They also ordered the company to improve its business practices, the report said Tuesday.

The confiscated food and beverages were produced in Fukushima, Saitama and Nagano.

Responding to a question about the reported seizure, Chief Cabinet Secretary Hirokazu Matsuno said Wednesday that the safety of food produced in Japan has been scientifically proven.

"The government will continue to urge the Chinese side to remove restrictions on food imports from Japan as soon as possible," Matsuno, Japan's top government spokesman, said at a news conference in Tokyo.

China has prohibited food imports from 10 Japanese prefectures, including those three, since an earthquake and ensuing tsunami in 2011 caused meltdowns at the Fukushima No. 1 nuclear plant.

The crackdown by local authorities came after Beijing began blanket radiation testing on seafood imports from Japan last month.

Rice imports from Japan, as well as other food and beverages, have faced delays at Chinese customs, sources familiar with the bilateral relationship said late last month, following the introduction of the testing.

Japan is considering starting to release treated water from the plant into the sea sometime between late August and early September. China has voiced strong opposition to the planned discharge.