* S&P:could lower Japan rating if fisc position erodes further
* Market takes announcement in stride
(Adds background, comments and market reaction, paras 3-11)
TOKYO, July 12 (Reuters) - Standard & Poor's may lower Japan's sovereign ratings if the government's fiscal position erodes further or there is a lack of concrete measures aimed at fiscal consolidation, the ratings agency said on Monday.
S&P said in a statement that stabilising the political environment is a key challenge for Japan to implement meaningful and sustainable fiscal consolidation following Japan's upper house election on Sunday.
Japanese government bonds and the yen took S&P's statement in their stride. Lead September 10-year JGB futures stood at 141.50 in evening session trade, after finishing the day's session 0.24 point higher at 141.45.
The yen was hovering near 89 yen to the dollar and last stood at 88.85 yen, down 0.2 percent from late U.S. trading on Friday.
Japan's ruling coalition, led by Prime Minister Naoto Kan's Democratic Party of Japan (DPJ), lost its upper house majority in Sunday's election, putting Kan's policies to deal with the country's massive debt at risk.
"As a result, a hung parliament is the most likely outcome, as leaders of opposition parties are rejecting the possibility of joining the coalition. A hung parliament would make it very difficult for the government to push through major policies," S&P said.
"As such, structural reforms, including those of the public sector and public pension system, and increases in the consumption tax rate will be difficult to implement in the new political landscape, and thus, potentially act as a negative factor on the sovereign ratings," it added.
S&P said the DPJ's party leadership election scheduled to be held in September 2010, could also affect government policy.
"Although Prime Minister Naoto Kan expressed his determination not to resign after the election, he may be pressured to change the current leadership to take responsibility for the election outcome, and this could destabilize the leadership of the DPJ as well as the government," it said.
S&P, which threatened in January to cut Japan's credit rating unless it produced a credible plan to rein in its soaring debt and lift growth in an economy plagued by persistent deflation, said it would consider revising the outlook for Japan's ratings to stable if the government consolidates its political foundations and takes concrete measures for fiscal consolidation.
S&P cut its outlook on Japan's long-term sovereign debt rating to negative from stable in January, while maintaining its AA long-term and A-1+ short-term local and foreign currency sovereign credit ratings. (Reporting by Masayuki Kitano)