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

The move was backed by the International Atomic Energy Agency, but drew sharp criticism from Beijing, which banned Japanese seafood imports as a result.

China indicated on Friday that it was edging closer to lifting the ban, saying talks with Japanese officials in Beijing this week had "achieved substantial progress".

"So far this year, the two sides have carried out several rounds of technical exchanges," Beijing's customs administration said in a statement, without giving further details.

Japan's Chief Cabinet Secretary Yoshimasa Hayashi said Beijing and Tokyo had "reached an agreement on the technical requirements necessary to resume exports of fishery products to China".

"Exports to China will resume as soon as the re-registration process for export-related facilities is completed," Hayashi told a news conference on Friday.

"We regard this as a major milestone."

China's foreign ministry said later Friday that Tokyo "has promised to take reliable and visible measures to ensure the quality and safety of Japanese aquatic products".

"Relevant authorities will study Japan's request to resume the export of Japanese aquatic products to China based on scientific and safety principles," spokesperson Lin Jian told a media briefing.

China previously said it had found no abnormalities in seawater and marine life samples it independently collected near the Fukushima plant in February, but indicated more tests were needed before revoking the ban.

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, whose ties with Japan have long been strained by Tokyo's imperial legacy, vociferously opposed the release of the treated wastewater, casting it as environmentally irresponsible.