South Korea on Tuesday said Japan's plan to release over 1.4 million metric tons of radioactive water announced earlier in the morning had "no scientific, technical problems."

But its view "does not translate into a show of approval or support for Japan's release plan," according to the government, given that Korea would ask Japan to stop release of filtered radioactive water immediately if it does not proceed according to its plan.

"We see that no scientific, technical problems were found in the wastewater release plan, as we confirmed that Japan will release the water according to its plan," Park Ku-yeon, first vice minister of the South Korea Office for Government Policy Coordination, said Tuesday at the daily briefing at the Government Complex Seoul.

"No change of course from the original plan will be tolerated, otherwise even a slight change will be deemed a threat to safety and hazard to the health of South Korean people, so we will immediately request Japan stop the water release."

This came hours after Japan announced plans to begin the release of more than 500 Olympic swimming pool's worth of contaminated water on Thursday. The release is expected to happen gradually over the course of a decade or more. Before the release, the water will be filtered through its Advanced Liquid Processing System and diluted with seawater.

Park added that Japan on Monday notified Korea of its plan to approve the Fukushima radioactive water release plan.

The announcement was made 12 years after eastern Japan was stricken by an earthquake and tsunami, killing over 18,000 and triggering a meltdown of Fukushima Dai-ichi nuclear power plant.

Park said that Seoul and Tokyo agreed to over five out of seven requests by President Yoon Suk Yeol to Japanese Prime Minister Fumio Kishida, during their summit earlier in July. Their latest meeting at Camp David in US did not touch upon the issue of Fukushima wter.

Seoul's nuclear expert will regularly visit an office of the International Atomic Energy Agency at the crippled Fukushima Daiichi power plant to enable on-site monitoring of the release. Korea fell short of dispatching its experts there -- in addition to Koreans taking part in the IAEA inspection team -- as initially requested, but Park said Korea "can still achieve what it is meant to achieve" as the adjustment in the plan was inevitable due to "diplomatic concerns."

Tokyo also agreed to disclose the data related to proceedings of the wastewater release for every hour including the activity concentrations of nuclides in the water, including tritium, before and during the release, and notify Korea's Foreign Ministry officials of any abnormalities in its release plan. Also, the environmental radiation dose will be measured again upon the change of source term, and radiation level of residents near the power plant will be carried out.

However, Park said Japan failed to deliver on Korea's request to add of the type of nuclides measurable on the ALPS filter due to a potential confusion involving Japan and the IAEA, and talks over more frequent inspections of the filters will resume after the upgrade in the facility.

"(Japan) accepted five requests out of seven and partly accepted one request, while the remaining one is still being discussed," Park said. "This is the government's official stance."

Park reiterated its stance that Korea has no plan to lift seafood import ban from eight prefectures including Fukushima.

Activist group Greenpeace blasted Korean government for "failing to exercise its rights as prescribed in international law to stop the Fukushima wastewater release by neglecting a potential hazard beyond Japanese jurisdictions."

It added that the failure is in line with Korea's stance of "prioritizing its pro-nuclear approach over safety," in its Korean statement Tuesday morning.