TOKYO, Feb 18 (Reuters) - It will take time to determine whether Japanese Prime Minister Shinzo Abe's policies to stimulate growth and end deflation will be effective, ratings agency Standard & Poor's said on Monday.

The policies could eventually lead to a reflation in Japan's economy, but public finances are likely to remain weak even if the government goes ahead with its plan to raise the 5 percent sales tax, the ratings agency said in a statement.

S&P reaffirmed its AA minus rating on Japan and maintained a negative outlook, meaning there is at least one-in-three chance of a downgrade in the coming fiscal year.

(Reporting by Stanley White; Editing by Shri Navaratnam) Keywords: JAPAN ECONOMY/S&P

(stanley.white@thomsonreuters.com)(+81 3 6441 1984)(Reuters Messaging: stanley.white.reuters.com@reuters.net)

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