Japan's Prime Minister Shigeru Ishiba has said he has no plans to quit, despite projections his ruling coalition will lose its majority in the country's upper house.

The expected result underscores voters' frustration with Ishiba, who has struggled to inspire confidence as Japan struggles against economic headwinds, a cost-of-living crisis and trade negotiations with the United States.

Many are also unhappy about inflation - particularly the price of rice - and a string of political scandals that have beleaguered the LDP in recent years.

The last three LDP premiers who lost a majority in the upper house stepped down within two months, and analysts had predicted that a significant loss in this election would yield a similar outcome.