TOKYO, July 16, 2025 (BSS/AFP) - Japan's unpopular ruling coalition faces tough upper house elections this weekend, opinion polls suggested, potentially ending Shigeru Ishiba's premiership after less than a year.

Ishiba, 68, has headed a minority government since October when he led the long-dominant Liberal Democratic Party (LDP) to its worst general election result in years.

The new surveys indicate that the ruling coalition of the LDP and the smaller Komeito party could lose its upper house majority on Sunday when 125 out of 248 seats are up for grabs.

The ruling bloc is "on course" to lose the majority, Kyodo News said on Tuesday, citing its latest poll.

It "would likely trigger calls for Prime Minister Shigeru Ishiba's resignation", Kyodo said.

Voters are unhappy about inflation -- in particular, the price of rice -- and scandals within the LDP, which has governed Japan almost uninterrupted for decades.

Since the October debacle -- Ishiba called the early elections after winning LDP leadership in September -- his coalition has been in a minority.

This has obliged the prime minister to rely on opposition parties to pass legislation, and losing the upper house majority would put him in a bind there too.

Ishiba has set a target for the coalition to win 50 upper house seats to maintain the majority, a level that in previous years would have seemed easy.

Kyodo, echoing other media surveys, predicted that the LDP would likely garner fewer than 40 seats, with Komeito also facing difficulties maintaining its 14 seats that are being contested.

The top-selling Yomiuri Shimbun on Wednesday also said the LDP could potentially only win 24 seats -- or 39 at most -- and Komeito between seven and 13.

"Maintaining a majority is becoming a difficult situation," the Yomiuri said.

- Projected to lose -

The influential Nikkei business daily also said the ruling bloc was projected to "lose significantly" and its prospects to keep the majority were in doubt.

Small, opposition parties with anti-establishment messages are seen as peeling support away from the LDP.

The anti-immigration Sanseito party in particular is enjoying significant momentum and may win more than 10 seats, up from two currently.

"They put into words what I had been thinking about but couldn't put into words for many years," a 44-year-old voter told AFP at a recent Sanseito rally.

"When foreigners go to university, the Japanese government provides subsidies to them, but when we were going to university, everyone had huge debts," she said.

The last time the LDP and Komeito failed to win a majority in the upper house was in 2010, having already fallen below the threshold in 2007.

That was followed by a rare change of government in 2009, when the now-defunct Democratic Party of Japan won a lower house majority.

It governed for a rocky three years that included the 2011 earthquake and Fukushima nuclear disaster before the LDP won a landslide in 2012.

If it loses the majority on Sunday, "Ishiba may need to step down", Toru Yoshida, a politics professor at Doshisha University, told AFP.

Japanese politics "will step into an unknown dimension of the ruling government being a minority in both the lower house and the upper house, which Japan has never experienced since World War II", Yoshida said.