The South Korean government says its own assessment shows Japan's plan to release treated and diluted water from the crippled Fukushima Daiichi nuclear power plant into the ocean would meet international safety standards.

The government issued a report on the outcome of its own investigation and analysis on Friday.

The report says Seoul has confirmed concentration of radioactive material will meet standards for ocean discharge if the release is carried out as planned.

It notes that the target for the level of tritium is set far below the standards. Tritium is known to remain in the water even after treatment.

The paper says the South Korean government has also confirmed that various devices have been installed at the facility to prevent contaminated water from being released in the event of an unexpected incident.

Government Policy Coordination Minister Bang Moon-kyu said as a result of South Korea's own scientific and technological safety assessment over the past two years, it was confirmed that the planned discharge will have no meaningful impact on the country's oceans.

Bang said as the water will be diluted by seawater in the Pacific and reach South Korea's coastal waters in four to five years' time, effects from tritium would be negligible.

Ban also said in view of lingering concerns among the South Korean public, the government will step up the monitoring of adjacent waters and radiation checks of fisheries products.

Water used to cool molten nuclear fuel at the Fukushima Daiichi plant mixes with rain and groundwater. The accumulated water is treated to remove most radioactive substances, but still contains tritium. The Japanese government plans to dilute the water to reduce the tritium level to about one-seventh of the World Health Organization's safety standard for drinking water before discharging it.