Tokyo ? Prime Minister Junichiro Koizumi’s hold on power looked increasingly precarious Monday, as his public support went into freefall after the firing of his foreign minister and an emboldened opposition submitted a no-confidence motion in Parliament.

Koizumi was defensive Monday in his first major policy speech of the year, opening with an allusion to his plunging popularity since he abruptly dismissed Makiko Tanaka as his top diplomat last week.

“With support for my government falling there have been fears that I might backtrack on reform, but my determination to push through reforms will not loosen,” he said. The lawmakers’ tepid applause contrasted with the usual uproarious welcome he has enjoyed in the legislature.

Koizumi took office in April last year as the self-styled “lionheart” who promised to overhaul the status quo. He quickly established himself as one of Japan’s most popular leaders in decades.

To drag Japan’s economy out of recession, he proposed reforms to rein in the crushing public debt, privatize government agencies and dismantle regulatory barriers to competition. He also promised to end backroom politics.

Observers have long said that the key to his chances of defeating entrenched interests within his own party and enacting reforms is his popularity. But polls show his approval rating falling from above 70 percent last month to about 50 percent now.

“As an administration the Koizumi administration may last a while longer, but the reforms are over,” said Shigenori Okazaki, a political analyst with UBS Warburg.

“Makiko Tanaka was one of the engines of his high public support, but you can’t fly on only one engine,” Okazaki said. He added that her dismissal indicates anti-reform forces in Koizumi’s Liberal Democratic Party may now be calling the shots.

Ally becomes critic

Now free from the constraints of the Cabinet, Tanaka wasted no time Monday in transforming herself from Koizumi ally into critic.

“In order to realize the prime minister’s pledges made in the speech, there first is a need for political reform,” she said after Koizumi’s speech.

Even the leader of the biggest of Koizumi’s three-member ruling coalition criticized the prime minister’s handling of the Tanaka affair.

“They (the public) want to know on what grounds the premier replaced her,” Kyodo News agency quoted New Komeito Party leader Takenori Kanzaki as saying. “He should have elaborated about his attempt to reform the Foreign Ministry through the personnel reshuffle.”

Kanzaki and the leader of the Conservative Party, the other coalition partner, reiterated their support for Koizumi but urged him to speed up reforms, Kyodo reported.

As if to underline his deepening isolation, Koizumi ended Monday’s speech by quoting a poem the late Emperor Hirohito composed months after Japan’s defeat in World War II: “Undaunted stands the pine tree in mounting snowdrifts.”

The image was meant to encourage Japan to be resilient in tough economic times, but it came across more as a reminder of the lonely political storm Koizumi himself faces in the months to come.

No-confidence vote

Japan’s four main opposition parties submitted a no-confidence motion in Parliament against Koizumi’s agriculture minister Tsutomu Takebe, accusing him of mishandling Japan’s outbreak of mad cow disease.

The motion is largely symbolic, because the ruling coalition has enough votes to defeat it when it goes to a vote in the legislature today.

But it was a clear sign that the opposition, long at a loss as to how to make inroads against Koizumi’s popularity, now senses it has a chance.

Japan is the only country in Asia with confirmed cases of mad cow disease, which wastes cows’ brains and is believed to be linked to a deadly human variant. Takebe has been accused of lacking a sense of crisis in investigating the outbreak.

Koizumi fired Tanaka because of a widely publicized dispute she had with ministry officials and a powerful ruling party lawmaker stemming from last month’s international aid conference for Afghanistan held here.

The first woman to become foreign minister, Tanaka had won a large following with voters for her straight-talking style and promises to clean up corruption in government.

According to a poll published Monday in the Asahi, a national newspaper, support for the Koizumi’s Cabinet dropped to 49 percent from 72 percent in a similar poll it conducted last month. It was the lowest approval rating for Koizumi in an Asahi poll since he took office.