Japan's conservative ruling camp braced for an expected election defeat on Sunday that could put pressure on hawkish Prime Minister Shinzo Abe to resign and usher in a period of policy paralysis and political confusion.

Polling stations across Japan opened at 7 a.m. (2200 GMT) on a cloudy morning.

The election for half the seats in parliament's 242-member upper house comes just 10 months after Abe, 52, took over and pledged to bolster Japan's global security profile, rewrite its pacifist US-drafted constitution, and nurture economic growth.

"I've always voted for the LDP, but this time I voted for the Democratic Party," said Toshio Muto, 75, a craftsman in Tokyo's Setagaya ward.

"I've seen the LDP pass a lot of legislation by force. I don't want this. I want change," he added.

The LDP and its junior partner, the Buddhist-backed New Komeito, need to win 64 seats to keep their majority in the upper house. The New Komeito is aiming for 13 seats.

Abe's coalition will not be ousted from government if it loses in the upper house, since it has a huge majority in the more powerful lower chamber, which elects the premier.

But laws will be hard to enact, threatening policy deadlock.

Abe's allies have said he need not step down even if the coalition loses and many analysts agree he might be able to hang on temporarily -- especially if the LDP wins at least 40 seats -- partly because of the lack of a convincing successor.- Reuters