* Deflation in Japan could require further easing
* Capital flows could trigger protectionist reactions
(Adds details, Gurria quote)
By Leigh Thomas
PARIS, Nov 3 (Reuters) - Central banks in the United States and the euro zone should only return monetary policy to more normal settings in 2012 due to weak economic growth, the OECD said on Wednesday.
The United States and the 16-country euro area should wait even longer to normalise interest rates if growth turned out weaker than expected, the OECD said in a set of policy recommendations.
"Because of weak growth in the U.S. and euro area, and provided that inflation expectations remain well anchored, the normalisation of interest rates should only proceed in earnest from the first half of 2012, at a pace that allows monetary policy to remain accommodating," said a statement published by the Organisation for Economic Co-operation and Development.
Turning to Japan, the OECD said in its recommendations that if the country remained mired in deflation then "rates could remain at current low levels throughout 2011 and 2012, and further exceptional easing should be implemented to give stimulus to the economy."
Japan cut interest rates virtually to zero last month.
"The immediate challenge for the monetary authorities is to get the timing for the exit from exceptional stimulus right," OECD Secretary-General Angel Gurria told a news conference hours before the U.S. Federal Reserve was expected to announce plans to buy billions dollars more of government bonds with new money in a bid to revive a struggling economy.
In a preview of detailed forecasts for its members' economies, which it will issue on Nov. 18, the Paris-based organisation estimated that the United States economy was set to grow 2.5-3.0 percent this year before slowing to a rate of 1.75-2.25 percent next year.
The euro zone economy was projected to grow 1.5-2.0 in both 2010 and 2011.
Japan's economy was forecast to grow 2.75-3.25 percent this year and slow to growth next year of 1.5-2.0 percent in 2011.
The OECD said ultra-low interest rates at the biggest central banks were driving flows of capital into faster growing emerging markets, lifting their exchange rates and prices for real estate and stocks.
OECD chief economist Pier Carlo Padoan told the news conference that some governments' efforts to keep capital from flooding in could "generate a non-cooperative environment and possibly also protectionist measures that add a drag on growth".
With its members' economies still weak, the organisation said governments' efforts to improve strained public finances should focus on cutting unproductive spending, although "it may be impossible to avoid tax increases".
The OECD also recommended governments adopt targets for limiting their debt as a percentage of gross domestic product and setting up independent fiscal watchdogs to track their efforts. (Reporting by Leigh Thomas, editing by Mike Peacock)