Japan will start releasing treated and diluted radioactive wastewater from the Fukushima Daiichi nuclear plant into the Pacific Ocean as early as Thursday — a controversial but essential early step in the decades of work to shut down the facility 12 years after its meltdown disaster.

Prime Minister Fumio Kishida gave the final go-ahead Tuesday at a meeting of Cabinet ministers involved in the plan and instructed the operator, Tokyo Electric Power Company Holdings, to be ready to start the coastal release on Thursday if weather and sea conditions permit.

Kishida said at the meeting that the release of the water is essential for the progress of the plant decommissioning and Fukushima prefecture's recovery from the March 11, 2011, disaster.

He said the government has done everything for now to ensure the safety, combat the reputational damage for the fisheries and to provide transparent and scientific explanation to gain understanding in and outside the country.

He pledged that the government will continue the effort until the end of the release and decommissioning, which will take decades.

A massive earthquake and tsunami destroyed the Fukushima Daiichi plant's cooling systems, causing three of its reactors to melt and contaminating their cooling water. The water is collected, filtered and stored in about 1,000 tanks, which fill much of the plant's grounds and will reach their capacity in early 2024.

The release of the treated wastewater has faced strong opposition from Japanese fishing organisations, which worry about further damage to the reputation of their seafood as they struggle to recover from the nuclear disaster.

Groups in South Korea and China have also raised concerns, turning it into a political and diplomatic issue.

The government and the plant operator, Tokyo Electric Power Company Holdings, say the water must be removed to make room for the plant's decommissioning and to prevent accidental leaks from the tanks

Junichi Matsumoto, TEPCO executive in charge of the water release, said in an interview with the Associated Press last month that the water release marks “a milestone”, but is still only an initial step in a daunting decommissioning process that is expected to take decades.

The easing of opposition from the fishing industry was key to the release because the government promised in 2015 not to start without “understanding” from fishing groups, after past accidental and unapproved discharges.

Masanobu Sakamoto, head of the National Federation of Fisheries Cooperatives, who met with Kishida on Monday, reiterated his organization's opposition to the release, but acknowledged that members of the fishing community have gained some confidence about the safety of the move. They still fear damage to their industry, he said, and welcomed the government pledge for support.

The government has offered funding totalling 80 billion yen (USD 550 million) for sales promotion and other steps, and for sustainable fishing operations.

The government and TEPCO say the water will be treated and then diluted with massive seawater to levels way safer than international standards, its environmental and health impact negligibly small.

The International Atomic Energy Agency in a final report in July concluded that the release, if conducted as designed, will cause negligible impact on the environment and human health.

Scientists generally support the IAEA view, but some say long-term impact of the low-dose radioactivity that remains in the water needs attention.

Kishida's government has stepped up outreach efforts to explain the plan to neighboring countries, especially South Korea, to keep the issue from interfering with their relationship.

Kishida said the effort has made progress and the international society is largely responding calmly to the plan. Still, Hong Kong said it would suspend exports from Fukushima and nine other prefectures if Japan went ahead with the plan, while China has stepped up radiation testing on Japanese fisheries products, delaying customs clearance.?