TOKYO - Japan's new government will have a shaky mandate when it takes office later this month, a poll indicated Wednesday, as party leaders acknowledged they must get to work immediately to deal with the country's severe economic problems.

Most Japanese voters chose the opposition in historic weekend elections because they were fed up with a half century of rule by the governing conservatives, not because they were enthused by what the opposition had to offer, according to the poll in the Asahi, a major national newspaper.

The poll found most voters remain skeptical about whether the victorious Democratic Party of Japan can make good on its promises to bring the world's second-largest economy out of its worst slowdown since the Second World War, rein in the powerful bureaucracy and restore Japan's international credibility after a succession of three prime ministers in three years.

The Democrats are expected to form a new government and name leader Yukio Hatoyama as prime minister on Sept. 16, replacing outgoing Taro Aso. In Sunday's elections, the Democrats won 308 of the 480 seats in the powerful lower house, giving them control of the chamber.

Separately, Hatoyama planned to speak with U.S. President Barack Obama late Wednesday, according to Japanese media reports.

National broadcaster NHK television reported that a phone conversation was planned for after 11 p.m. (1400 GMT, 10:00 a.m. EDT). Hatoyama's party could not immediately confirm the report, but said he would be returning to his office at that time.

Hatoyama said his party started talks Wednesday with two smaller ones -- the Social Democratic Party and the People's New Party -- to work together in forming a new government.

"Today we started policy discussion to seek a three-party coalition," Hatoyama told reporters. "The key is how much we can agree on policies. But I believe we can produce final results fairly soon."

Aso has announced he will step down as president of the conservative, pro-big business Liberal Democratic Party, which has led Japan for all but nearly 11 months since it was created in 1955.

"We will do all we can to ensure a smooth transition," chief Cabinet spokesman Takeo Kawamura said Wednesday.

In the first major poll since Sunday's elections, the Asahi said 81 per cent of respondents felt the reason for the Democrats' win was that voters wanted a new administration. Only 38 per cent said the victory was because of support for the party's polices, it said.

Only 32 per cent of respondents said they felt the Democrats would be able to change the government significantly, while 46 per cent said they would not, the poll said. It put the Democrats' approval rating at just 39 per cent.

The poll was a random telephone survey of 1,104 eligible voters conducted on Monday and Tuesday. It reported direct results and so gave no margin of error, but a poll of that size would generally have a margin of about three percentage points.

"They must demonstrate their political leadership, and policy implementation should be as fast as possible," said Susumu Kato, chief economist at Calyon Capital Markets Asia in Tokyo.

The Democrats acknowledged they will face tough economic realities when they take over.

"The economy is in a severe condition," Katsuya Okada, a senior Democratic Party executive, said Wednesday. "We deeply feel the responsibility of what we must do."

Japan, the world's second-largest economy, climbed out of a yearlong recession in the second quarter, but its recovery is still weak. The unemployment rate has risen to a record 5.7 per cent, its highest since the Second World War.

The Democrats have proposed cash handouts to families and farmers, toll-free highways, a higher minimum wage and tax cuts. The estimated bill comes to 16.8 trillion yen (US$179 billion) if fully implemented.

The party has said it plans to cut waste and rely on untapped financial reserves to fund their programs.

Kato, the economist, said he thinks the Democrats are on the right track.

"Households are hurting," he said. "For now, they are talking about taking the appropriate steps."