Japan's Supreme Court on Wednesday ruled constitutional a disparity of up to 3.00 times in the weight of a single vote between the most and least populated constituencies in an Upper House election last year.

Following 16 conflicting rulings from lower courts, the top court rejected the plaintiffs' demand for the outcomes of the House of Councilors election held on July 21, 2019, to be nullified.

"The value of each vote was not in a state of extreme inequality," the presiding justice, Naoto Otani, said, recognizing efforts made by parliament to redress the disparity.