Experts from China will join those from Canada, South Korea and the UN's International Atomic Energy Agency (IAEA) in collecting samples of water, sediment and marine creatures from October 15 to 23.

The survey will also collect seafood samples from the region's markets, the import of which has been banned by Beijing.

China has repeatedly criticised the release of water once used to cool the plant's reactors.

"It's important that we ensure the transparency of our monitoring process," a Japanese official told reporters Wednesday, confirming it would be the first extensive involvement by Chinese experts since the release of water started in August.

Samples collected by the teams will be sent back to labs in their home countries for independent review, and the IAEA will evaluate and publish those results, the UN body said in a press release.

Tokyo Electric Power (Tepco) has said the decades-long process will involve some 1.34 million tonnes of treated wastewater from the plant, which suffered a meltdown following a devastating 2011 earthquake and tsunami.

Japan has insisted throughout that the treated water, which is being released in batches, poses no health risks, a view backed by the IAEA.

Tepco says the wastewater has been filtered of all radioactive elements except tritium, which falls within safe levels.

But Beijing has been pointed in its public criticisms, accusing Japan of treating the ocean "like a sewer" and instituting a ban on Japanese seafood.

Russia, which also has frosty relations with Japan, is reportedly considering following suit on the seafood ban.