Prime Minister Shinzo Abe's Liberal Democratic Party, along with junior coalition partner Komeito, aim to win a combined majority of the 121 seats up for grabs in an Upper House election Sunday.

Abe has presented the vote as a referendum on his Abenomics stimulus policies of bold monetary easing, flexible fiscal spending and reforms.

An election is held every three years for half of the Upper House's 242 members, who have six-year terms.