Due for routine inspections, two more of Japan’s 54 nuclear reactors are scheduled to come offline later this month. Three more will follow in August.

Under ordinary circumstances, these shutdowns would be temporary. Instead, they loom as an urgent problem for Japan, whose government — itself divided over nuclear policy — has not yet mustered the political will or the popular support necessary to restart reactors once they are idled.

Unless that changes in the coming months, Japan faces a scenario in which all of its reactors could be shut down by April, because many more inspections are scheduled soon. The country’s nuclear policy mandates that reactors come offline after every 13 months of operation for checkups. By extension, Japan now faces a formal countdown to win local support for nuclear power or face massive economic consequences.

In recent days, Japan’s central government has succeeded only in undermining its cause. At the urging of Prime Minister Naoto Kan, Japan said Wednesday that it would conduct stress tests on all of its nuclear stations, evaluating their resistance against plane crashes, natural disasters and other extreme events. But the new safety checks contradicted the government’s June 18 declaration that the plants had already taken all necessary measures to ensure safety.

The crisscrossing messages reflect what political analysts describe as a growing gap between Kan, who has vouched for greater reliance on renewable energy, and Banri Kaieda, head of the Ministry of Economy, Trade and Industry, which has long championed the safety of nuclear power.

Last month, Kaieda said in a statement that “there is no problem regarding safety concerning the continued operation and restart of nuclear power stations.”

On Friday, Kan apologized for waiting too long to order the stress tests, saying the late decision caused confusion. “My instruction was inadequate,” Kan said.

Before the March 11 earthquake and tsunami that triggered three separate meltdowns at the Fukushima Daiichi nuclear plant, Japan had been the world’s third-biggest nuclear power generator. Its 54 reactors supplied roughly 30 percent of the country’s electricity.

But now, only 17 of Japan’s reactors are operating as usual, with two more running in test mode. Though the Fukushima accident dealt a direct blow to the Tokyo Electric Power Co. — the main electricity supplier in a region of 42 million — other major power companies now face growing capacity shortfalls of their own.

The Kansai Electric Power Co. has asked consumers to cut consumption by 15 percent this summer. Japan’s government said at least four other utilities — Tohoku Electric, Hokuriku Electric, Shikoku Electric and Kyushu Electric — would be unable to meet peak electricity demands beginning this winter if their reactors do not resume.

The confusion over restarting reactors has already caused direct consequences in Saga prefecture, on Japan’s southwestern island of Kyushu. That’s where Kyushu Electric Power Co., one of the country’s regional monopolies, operates the Genkai nuclear power plant. Before the stress-test announcement, Japan’s central government had nearly secured local approval to restart two of Genkai’s reactors. The mayor was on board. And the governor, according to Japanese media reports, was leaning that way.

But the policy change prompted Genkai’s mayor, Hideo Kishimoto, to withdraw his support. Although local government approval isn’t legally necessary to restart reactors, Japan’s electric operators have always considered it a de facto requirement.

Japan’s pro-nuclear faction had hoped that by restarting the reactors at Genkai, other local governments would quickly allow other plants to resume operation. Kaieda, in particular, had tried to win approval for the resumption, visiting Saga on June 28. The visit came two days after an open forum in the city of Saga — broadcast on cable television and online — in which viewers could voice comments or concerns by e-mail.

The only problem: As it turned out, Kyushu Electric had tried to manipulate the debate by ordering some of its employees, as well as those of its affiliates, to write messages in favor of resumption.

After the charade made national media headlines this past week, Chief Cabinet Secretary Yukio Edano called the scheme “truly outrageous” and said it would undermine efforts to restart the reactors.

“There’s no strategy” for coping with the energy shortages, said Kazumoto Irie, a former economy ministry official who is a visiting professor at the University of Tokyo. “And at the same time, there is a growing sentiment to phase out nuclear power. . . . We need a medium-term energy plan — for the next five or 10 years — to ensure the energy supply to households and businesses. I fear that, already, businesses are quietly leaving.”

Special correspondent Akiko Yamamoto contributed to this report.