Tokyo, July 20 -- Japan's ruling coalition is certain to lose its majority in the House of Councillors after Sunday's election, an outcome that will pile pressure on embattled Japan's Prime Minister Shigeru Ishiba, who has vowed to stay on despite yet another heavy blow to his party, Kyodo News reported.

The cards are stacked against PM Ishiba, with all major opposition parties ruling out joining the Liberal Democratic Party and its partner Komeito in an expanded coalition.

The ruling coalition has now been deprived of majority control in both houses of parliament, the upper house and the more powerful House of Representatives -- a very rare situation for a government in post-war Japan. Opposition support will become even more crucial f...