Support for the government of Japanese Prime Minister Yukio Hatoyama, who faces key decisions on next year's budget and relocating a U.S. airbase, have sunk as low as 48 percent in surveys issued on Monday and at the weekend.

Many voters said Hatoyama had failed to show leadership since sweeping to power in a landslide August election victory.

About a third of respondents in the three surveys said they did not back Hatoyama's Democratic Party-led government as politicians gear up for an upper house election in mid-2010.

Hatoyama faces a tough decision on how to keep a promise to hold new bond issuance to 44 trillion yen ($486.5 billion) in the fiscal year from April despite falling tax revenues and may backtrack on campaign pledges aimed at putting more cash in the hands of consumers.

He has also delayed a solution on relocating a U.S. airbase on Okinawa, irritating security ally Washington.

The most dramatic slide in support came in a poll by the Asahi newspaper, showing 48 percent of respondents backed the government, compared with 62 percent about a month ago. About 74 percent said that Hatoyama had failed to demonstrate leadership.

The Mainichi newspaper showed support had fallen to 55 percent, down from 64 percent in November.

But Hatoyama's troubles have not translated into good news for the opposition Liberal Democratic Party (LDP). The Asahi said 42 percent backed the Democrats against 18 percent for the LDP.

The Democrats need to win a majority in the upper house to free themselves from an awkward coalition with two tiny parties. A ruling bloc loss would revive a parliamentary deadlock in which an opposition-dominated upper house could delay legislation.

(Reporting by Isabel Reynolds; Editing by Ron Popeski)