Japan's leader Shigeru Ishiba faces mounting political pressure as his ruling coalition is set to lose its majority in the House of Councilors on Sunday.

Exit polls suggest Prime Minister Shigeru Ishiba's coalition is likely to lose a majority its majority in the smaller of Japan’s two parliamentary houses in a key election.

Japanese voters headed to the polls on Sunday in a tightly contested election amid public frustration over rising prices and the imminent threat of US tariffs. The ruling Liberal Democratic Party (LDP) and its junior coalition partner Komeito need to secure a combined 50 seats to retain an overall majority in the upper house but the latest polling shows they might fall short.