Conservative President Yoon Suk Yeol's government has come under criticism as it defended the position that its own assessment found no problems with the scientific and technical aspects of Japan's plan.

The region last year recorded 35 natural hazards, including floods and storms, that killed more than 700 people, according to the report.

The growing frequency and intensity of severe weather is symptomatic of global, human-driven climate change that is fueling extremes, experts say, with current heatwaves expected to persist through August.

The Princess Empress was travelling from Bataan province, near the capital Manila, to the central province of Iloilo when it had engine trouble and sank in rough seas off Oriental Mindoro province.

Reports say that water temperatures on the West Coast of the South Island are currently 4 degrees above average.

Ice shelves, permanent floating sheets of frozen freshwater attached to land, take thousands of years to form and act like buttresses holding back glaciers that would otherwise easily slide off into the ocean, causing seas to rise.

The water, used to cool reactors in the aftermath of the 2011 nuclear disaster, is being stored in huge tanks in the plant, and amounted to more than 1.3 million tonnes by July.

The report follows the latest UN climate assessment, which warned that humanity must drastically cut its greenhouse gas emissions or face increasingly catastrophic changes to the world's climate.

Researchers have found that the key driver of ice loss was change in temperature, though shifts in ice mass also played a lesser role.