South Korea's main opposition Democratic Party decided on Wednesday to submit a letter to the United Nations (UN) Human Rights Council to protest Japan's planned discharge of radioactive wastewater into the ocean.

Lee Jae-myung, chief of the Democratic Party, held a signing ceremony for the letter, together with Woo Won-shik, head of the party's prevention committee, on the release of Japan's nuclear-contaminated wastewater.

The letter is scheduled to be submitted later this month to the UN special rapporteurs on toxics, human rights, environment and right to food after recruiting additional petitioners from civil society.

The Democratic Party say in the letter that the dumping of the radioactive wastewater into the marine environment will violate the fundamental human rights convention and the scientific safety standard and principle.

The party noted that the dumping will pose serious risks to the marine environment and the enjoyment of human rights of affected populations including future generations, stressing that alternatives should be actively considered and pursued according to safety standards.

Despite strong opposition from neighboring and Pacific island countries, as well as local fishermen over the irreversible impacts on the marine environment and public health, the Japanese government has been pushing for the release of the radioactive wastewater from the Fukushima nuclear power plant hit by a massive earthquake and an ensuing tsunami in March 2011.

Japan is mulling discharge the nuclear-contaminated wastewater into the sea beginning between late August and early September, Kyodo News reported on Monday.

(With input from Xinhua)