TOKYO (Reuters) - Japanese Prime Minister Yukio Hatoyama on Monday urged his party to go all out to win a vital upper house election this year, as economic and diplomatic woes erode support for his three-month-old administration.

Since the Democratic Party won an August general election, voter support has slid below 50 percent on growing doubts over Hatoyama's ability to manage Japan's massive debt and ailing economy or to patch up ties with security ally Washington.