Japan and China have been at loggerheads over the discharge of the wastewater, which was used to cool the reactors after the 2011 meltdown.

Japan insists it has been safely treated, but China has criticised the release and banned Japanese seafood imports.

"A dialogue between Japanese and Chinese experts on the discharge of... treated water into the ocean (by the Fukushima plant) was held in Dalian, China on March 30 to exchange views on technical matters," Tokyo's foreign ministry said in a statement.

The announcement comes after Japanese Prime Minister Fumio Kishida met with Chinese President Xi Jinping in November and said science-based discussions would take place at the expert level.

Japan began gradually discharging some of the 1.34 million tonnes of wastewater that have accumulated since the disaster into the Pacific in August, sparking a diplomatic row with China and Russia, both of which banned seafood imports.

China has accused Tokyo of treating the sea as a "sewer", but Japan insists the discharge is safe, a view backed by the UN atomic agency.

Kishida called on China at the November Asia-Pacific summit in San Francisco to make an "objective judgment" on the safety of Japan's seafood, which is a major industry in the country.

Japan began releasing the treated wastewater because the nuclear facility was running out of space to build more water tanks, and it needed to make room for the much more hazardous task of removing radioactive fuel and rubble from the three stricken reactors.