Japanese Prime Minister Yoshihiko Noda reshuffled his cabinet  today, just four months after taking office, in an effort to win bipartisan support for an unpopular sales tax hike.

Noda replaced five members of his cabinet, two of whom had been censured by the upper house over a series of gaffes.

Defense Minister Yasuo Ichikawa, who sparked outrage in Okinawa when he compared the planned relocation of a U.S. marine base to rape, will be replaced by upper house lawmaker Naoki Tanaka.

Jin Matsubara replaces Consumer Affairs Minister Kenji Yamaoka, who was criticized for ties to dubious business groups and a gaffe comparing the collapse of the euro to the tsunami.

Noda also appointed former Foreign Minister Katsuya Okada as the deputy in charge of tax and social security reform, a move that could further divide the ruling Democratic Party of Japan. Supporters of veteran powerbroker Ichiro Ozawa are weary of Okada, who led the push to suspended Ozawa's party membership, following his indictment over a political funding scandal.

The cabinet overhaul comes as Noda looks to forge ahead with a bill to double Japan's 5 percent sales tax in two stages, something that hasn't been done since 1997. The prime minister has said the tax hike is necessary to rein in a public debt that is now twice the $5 trillion economy. But opposition lawmakers, who control the less powerful upper house of parliament, refused any discussion of the increase until the censured ministers were removed.

"Both were very much disliked by the opposition party," said Koichi Nakano, political science professor at Sophia University. "If they were not removed, the parliament would not be cooperative with anything Noda would try to do, with the ordinary session that's about to begin."

Even with new cabinet members, Nakano says Noda faces an uphill battle.

Japan's divided parliament makes it difficult for the prime minister to pass legislation. Noda also faces opposition within his own party, from Ozawa supporters who argue that raising taxes would hurt an already weak economy, at a time when Japan is tasked with a massive rebuilding effort following the triple disasters.

Since taking office in September, the prime minister's public approval ratings have declined rapidly. A Kyodo News agency poll taken earlier this month showed just 35.7 percent of the public supported him, down from 44.6 percent a month ago.

"Public perception is that this government in particular is not in a position to increase the consumption tax," Nakano said. "For as long as we know, they have been saying they would not increase the tax, during the length of this parliament. So they're seen as a government that's breaking public promises"