TOKYO (AP) -- Japan’s lower house voted Tuesday to double the country’s sales tax to 10 percent over three years in a bid to rein in the country’s bulging national deficit.

But the vote may have weakened Prime Minister Yoshihiko Noda’s grip on power as the measure faced strong opposition within the ruling party led by party elder Ichiro Ozawa that believes the tax hike is premature and will further weaken the economy. Ozawa and his supporters have threatened to bolt the party over the tax issue.

The bill cleared by a vote of 363-96, with support from the two biggest opposition parties. The tax bill still must pass the less powerful upper house to become law, which is expected.

It calls for raising the sales tax from 5 percent to 8 percent in 2014, and then to 10 percent in 2015.

Noda, who has been in power only since last September, has said the tax hike is needed to reduce Japan’s bulging national deficit, which is more than twice its gross domestic product. He has made the tax move the centerpiece of his efforts to tackle Japan’s major structural problems.

Japan was hit hard by last year’s devastating earthquake and tsunami but has been sputtering for years under one of the largest public debt burdens in the developed world.

“This reform is not just for our generation. But for our future,” Noda said before the vote.

But even Noda’s government projects the step will take only a modest bite out of Japan‘s deficit. The Cabinet Office forecasts that doubling the sales tax will boost revenues by 13.5 trillion yen ($170 billion) annually by 2015. Japan currently runs a deficit of about 45 trillion yen ($563 billion) a year.

Some economists warn that the tax hike will end up undermining Japan’s economy by weakening consumer demand at a time when wages are stagnant and people are already holding back on spending. Key auto and electronics exporters, meanwhile, have been battered by the strong yen and intensifying competition from Asian rivals.

While last year’s tsunami disaster has made many Japanese more willing to make sacrifices to help their country recover, though they are concerned over how the higher taxes will affect their personal finances.

“The tax hike will bring about another headwind to the economy, which is weaker consumption,” said Hiromichi Shirakawa, Credit Suisse’s chief Japan economist, who argued that the tax hike might boost revenues over the next couple years but end up dragging on economic growth and erode income taxes and corporate taxes, thus worsening Japan‘s deficit over time. Instead, the government should focus on ways to cut public spending and bolster the economy, and then raise the sales tax, he said.

“In 10 years’ time, we may see a more disastrous fiscal situation,” Shirakawa warned.

The economic debate was somewhat overshadowed by the political in-fighting. Influential power broker Ozawa, who has often criticized Noda and controls a bloc of lawmakers in the ruling Democratic Party, has suggested he may leave the party and take as many lawmakers as he can with him to form a new party.

A party split could make it harder for Noda to work with parliament to achieve his other policy goals. If 54 or more lawmakers join Ozawa, Noda’s party would lose its majority in the lower house of Parliament altogether and could be forced to call general elections.