Japan's Diet has enacted legislation to reform the electoral system, including the addition of six seats to the 242-seat Upper House.

The legislation cleared the Lower House with majority support from the governing Liberal Democratic Party and its coalition partner Komeito.

The increase in seats to the upper chamber will be the first since 1970. The LDP proposed the bill, saying the reform will help correct the disparity in the value of each vote. The opposition criticized the proposal.

The new legislation introduces a special quota to the proportional representation system so that some candidates are elected according to their place on a list submitted by each party.

The new law will be in effect for the Upper House election next summer. Half of the seats in Japan's upper chamber are up for grabs every three years. The latest reform will see three seats added in the 2019 election and three more in 2022.