The Japanese government is poised to release treated radioactive water accumulated at the crippled Fukushima nuclear plant into the sea despite opposition from fishermen, sources familiar with the matter said Friday.

It will hold a meeting of related ministers as early as Tuesday to formally decide on the plan, a major development following over seven years of discussions on how to discharge the water used to cool down melted fuel at the Fukushima Daiichi plant.

Photo taken on Feb. 13, 2021, from a Kyodo News helicopter shows tanks storing treated radioactive water behind reactor buildings at the Fukushima Daiichi nuclear power plant. (Kyodo)

The treated water containing radioactive tritium, a byproduct of nuclear reactors, is said to pose little risk to human health because even if one drinks the water, so long as the tritium concentration is low, the amounts of tritium would not accumulate in the body and would soon be excreted.

There is also no risk of external exposure even if the water comes in contact with skin.

Still, concerns remain among Japan's fisheries industry and consumers as well as neighboring countries such as South Korea and China.

The government has said it cannot continue postponing a decision on the disposal issue, given that the storage capacity of water tanks at the Fukushima complex is expected to run out as early as fall next year.

It asserts that space needs to be secured on the premises, such as for keeping melted fuel debris that will be extracted from the damaged reactors, to move forward with the decades-long process of scrapping the complex.

Plant operator Tokyo Electric Power Company Holdings Inc. says it will take around two years for the discharge to start.

The government had initially hoped to make a decision on the discharge of the treated water in October last year but later decided it would need more time for discussions amid concerns about reputational damage to marine products.

But Prime Minister Yoshihide Suga said Wednesday his government will decide "in a few days" whether to release the water after meeting with Hiroshi Kishi, head of the national federation of fisheries cooperatives, who conveyed his organization's continued strong opposition to the plan.

On media reports that Japan is poised to discharge the water into the sea, China and South Korea responded by calling on Tokyo to consider it carefully and with transparency.

China urged Japan to make a cautious decision on the matter, saying, "The radioactive material leakage caused by the Fukushima nuclear accident in Japan has had a profound impact on the marine environment, food safety and human health."

The Japanese government should disclose adequate information and "make a careful decision based on full consultation with neighboring countries," Chinese Foreign Ministry Spokesman Zhao Lijian told reporters in Beijing.

South Korea's Foreign Ministry said in a statement, "Our government has always emphasized that the Japanese government needs to transparently open up information over how it deals with contaminated water."

The ministry added it wants to continue to have close discussions on the issue with Japan and other countries concerned as well with international organizations like the International Atomic Energy Agency.

China and South Korea are among 15 countries and regions that continue to restrict imports of Japanese agricultural and fishery products more than 10 years after the Fukushima nuclear crisis, caused by a devastating earthquake and tsunami in 2011.

In February last year, a government panel proposed various options for disposing of the water, including releasing it into the ocean as well as evaporating it.

The following month, TEPCO drafted a plan to dilute the water to below the legal limit for concentration of radioactive materials before releasing it in the sea.

The Fukushima Daiichi plant, which suffered core meltdowns following the natural catastrophe in March 2011, continues to generate massive amounts of radiation-tainted water after it is used to cool melted fuel.

The water is treated using an advanced liquid processing system, or ALPS, to remove most contaminants and stored in tanks on the complex premises. The process, however, cannot remove tritium, a radioactive byproduct of nuclear reactors.

The IAEA has backed the Japanese government's plan to dispose of the water, saying releasing it into the sea meets global standards of practice in the nuclear industry.

The Geneva-based body's Director General Rafael Grossi, during his visit to the Fukushima complex in February, said it is a common way to release water at nuclear power plants, even when they are not in emergency situations.

Japan's industry minister Hiroshi Kajiyama said to Grossi in a videoconference last month that Japan wants the IAEA to conduct a scientific and objective review of the method of disposal of the water and openly convey its view to the international community.

Kajiyama said at the time that the IAEA's message is vital in dispelling concerns and reputational worries over the safety of the water that exist domestically as well as in the neighboring countries.