Japanese Prime Minister Naoto Kan, right, speaks to Sadakazu Tanigaki, the leader of main opposition party, during the one-on-one debate at the parliament in Tokyo, June 1, 2011. (AP)

Japanese Prime Minister Naoto Kan will face a no-confidence vote on Thursday that could force him from office amid this country’s most severe crisis since World War II.

Though the ouster attempt is unlikely to work — the vote will take place in the lower house of parliament, which Kan’s ruling party controls — it threatens to further undermine political unity at a time when Japan faces major policy questions about disaster reconstruction.

The no-confidence measure was submitted Wednesday by opposition leaders, who have battered Kan for weeks over his handling of the nuclear emergency at the Fukushima Daiichi plant and his allegedly slow response to the need for disaster relief.

That Japan could even plot a leadership change less than three months after its mega-catastrophe reaffirms the dysfunction of a political system where neither the status quo nor the immediate alternatives is popular. According to the latest polls, only 20 percent of Japanese citizens want Kan to step down immediately. But four in five don’t think Kan’s government has done a good job since March 11.

If the no-confidence measure passes with a majority vote, Kan must either step down or dissolve the powerful lower house, triggering fresh elections. Kan’s ruling Democratic Party of Japan and a tiny ally party control 309 seats in the 480-seat house; the no-confidence measure will pass only if at least 70 members of the ruling coalition rebel against Kan.

Political analysts said such a scenario is far-fetched, especially with DPJ leaders threatening to punish, even expel, party members who push for Kan’s resignation.

But if nothing else, the vote will exacerbate long-standing strains within the DPJ, whose high-profile members — political dealmaker Ichiro Ozawa and former prime minister Yukio Hatoyama — have become vocal critics of Kan’s. Ozawa, despite his own string of scandals, retains a group of roughly 40 loyalists who are willing to back the no-confidence motion, according to reports in the Japanese news media.

The motion was submitted by leaders of the Liberal Democratic Party and New Komeito, the largest opposition groups, as well as the Sunrise Party. LDP leader Sadakazu Tanigaki hinted that cross-party cooperation would be possible if Kan was to resign. But Kan has refused, saying he “cannot abandon” his responsibilities.

In a blistering exchange in parliament Wednesday, Tanigaki told Kan: “You have no personal virtues or ability to unite your own party members. I’m telling you to quit.”

Japan has been held back in recent years by revolving-door leadership, with none of the four previous prime ministers keeping their jobs for more than 12 months. Kan, who took office June 8, has already weathered earlier threats. On March 11, with his approval rating near 20 percent, he endured a grilling in parliament from opposition leaders. Pundits said his resignation seemed imminent.

Hours later, a 9.0-magnitude earthquake and the resulting tsunami dramatically changed Japan’s political needs and, in effect, granted Kan a reprieve. But now Kan finds himself again in a vulnerable position, having failed to convert the national trauma into popularity.

Opponents say Kan has struggled to coordinate Japan’s post-earthquake strategy — and public message — in response to the nuclear emergency at Fukushima Daiichi. Information about dangers has come too late or required embarrassing corrections. A poll conducted by Fuji Television and the Sankei newspaper showed Monday that more than 80 percent of respondents did not trust government-issued information about the nuclear crisis — even though much of the problematic information has come via the Tokyo Electric Power Co., operator of the facility.

Just four days into the nuclear emergency, Kan set up a joint response headquarters for Tepco and the government. That hasn’t prevented the utility company and politicians from squabbling about actions taken early on in the crisis.

Last week, for example, parliament spent hours debating why, for 55 minutes on March 12, critical seawater injections had been stopped at one of the reactors. The debate continued until Tepco announced that, upon further investigation, injections never had been stopped.

Some DPJ politicians have warned of a leadership vacuum if Kan steps down, adding to Japan’s difficulties as it tries to fund massive reconstruction in the northeast. Kan’s administration raised the prospect this week that Japan should gradually raise its 5 percent consumption tax to pay for the repairs, doubling it by 2015. But the country also faces broad concerns about its aging population, shrinking workforce and ballooning debt.

If the motion against Kan succeeds, opposition parties and the DPJ rebels could try to cobble together a coalition that would ease passage of such key legislation. But “there is no higher principle” tying those groups together, said Naoto Nonaka, a political science professor at Tokyo’s Gakushuin University. “It is highly inconceivable that they can work together.”

Special correspondent Akiko Yamamoto contributed to this report.