China and Japan are key trading partners, but increased friction over territorial rivalries and military spending has frayed ties in recent years.

Japan's brutal occupation of parts of China before and during World War II remains a sore point, with Beijing accusing Tokyo of failing to atone for its past.

Japan began gradually releasing treated wastewater from the stricken Fukushima nuclear plant into the Pacific Ocean in 2023.

The move was backed by the International Atomic Energy Agency and the plant operator TEPCO says all radioactive elements have been filtered out except for tritium, levels of which are within safe limits.

But it drew sharp criticism from Beijing, which banned imports of Japanese seafood as a result. Russia later followed suit.

Samples from long-term monitoring of nuclear-contaminated water from Fukushima had "not shown abnormalities", China's General Administration of Customs said in a statement Sunday.

As a result, China "decided to conditionally resume" seafood imports from Japan, with the exception of imports from 10 of the country's 47 prefectures, including Fukushima and Tokyo, which remain banned.

The Japanese government received the decision "positively", Kazuhiko Aoki, deputy chief cabinet secretary, told reporters in Tokyo.

But Japan "will strongly demand the Chinese side lift remaining import regulations on seafood from 10 prefectures", he added.

Japanese Agriculture Minister Shinjiro Koizumi also called China's move "a major milestone".

In 2011, a huge earthquake triggered a deadly tsunami that swamped the Fukushima nuclear facility and pushed three of its six reactors into meltdown.

China vociferously opposed the release of the treated wastewater, casting it as environmentally irresponsible. But in September last year it said it would "gradually resume" importing the seafood.

Production companies that had suspended trade must reapply for registration in China and would be "strictly" supervised, Beijing's customs administration said Sunday.