Tokyo, Japan (CNN) -- Japanese Prime Minister Naoto Kan vowed to keep his job Sunday despite a defeat at the polls for his Democratic Party of Japan, which apparently failed to gain a majority in the upper house of parliament.
"I am very sorry that we could win far less than what we (had) originally anticipated," he said at a news conference. "... I take this outcome very seriously and will make a fresh start by continuing responsible government management."
Kan's initial honeymoon period after taking office ended when he said he would like to start a debate on raising the consumption tax in order to fix the nation's financial problems. He suggested an opposition party's proposal to raise the tax to 10 percent might be a starting point for the debate.
Nationally televised election programs announced that exit polls showed the party winning about 43 seats and called the election result a defeat for ruling party.
Half of the upper house seats, or 121 out of the total of 241 seats, were up for grabs in Sunday's national election. Results will not be finalized until Monday.
The Democratic Party of Japan marked a landslide victory in the general election last August, but lost its momentum after the sudden resignation of former Prime Minister Yukio Hatoyama and his successor Kan's hint at a possible hike in the consumption tax, which came soon after his inauguration.
The election was seen as a test for Kan. Since the party is defeated under his leadership, he could step down voluntarily. But he indicated Sunday he would not.
Kan, who became Japan's leader on June 4, said Sunday his remark on the tax was not adequately explained.
"I made my remarks about the consumption tax off the cuff and was not able to give enough explanation to the voters," he said.
The election dealt a blow to Kan, as opposition parties in the parliament can potentially block any bills except budgets in the absence of a ruling party majority.
CNN's Yoko Wakatsuki contributed to this report.