By Susan Mathew
March 20 (Reuters) - Australia and New Zealand shares fell on Monday in thin trade, on worries over global trade protectionism and as Fletcher Building stocks saw a steep fall after the builder cut its full-year earnings forecast.
Australian shares also tracked Wall Street, which ended flat in its previous session, and the outcome of the G20 summit over the weekend in Germany.
Breaking a decade-long tradition of endorsing open trade, finance ministers and central bankers made only a token reference to trade in their communique on Saturday. was seen as a clear defeat for host nation Germany, which fought the new U.S. government's attempts to water down past commitments.
"There seems to be an element of risk aversion but nothing really substantial or sinister. Markets have had a good run. There is an element of euphoria being priced in," said Chris Weston, an institutional dealer at IG Markets
"There are contrary signals suggesting that we might see a bit more downside in the short term with the G20 over the weekend. There is some fragmentation about their views."
New Zealand's benchmark S&P/NZX 50 index .NZ50 fell 1.2 percent, or 85.76 points to 7,072.38, as its biggest construction and building supplies company Fletcher Building FBU.NZ lost as much as 13.2 percent, logging its worst day since October 2011.
The company cut its full-year operating earnings guidance by about 13 percent to NZ$610 million - NZ$650 million ($428-$456 million. Australian shares of Fletcher FBU.AX fell as much as 12.5 percent in their fifth straight session.
The S&P/ASX 200 index .AXJO was down 0.32 percent or 18.346 points at 5,780.3 at 0120 GMT with losses being broad based.
Three of the 'Big Four' banks in Australia fell between 0.2 percent and 0.5 percent. Shares of National Australia Bank NAB.AX , however, gained 0.6 percent.
The materials sector .AXMM lost 0.5 percent. Miner Rio Tinto (LON:RIO) RIO.AX shed 0.7 percent. Chinese steel and iron ore futures had dropped on Friday. IRONORE/
The gold index .AXGD fell 1.5 percent as Newcrest Mining NCM.AX fell 0.8 percent while St. Barbara SBM.AX and Evolution Mining EVN.AX declined 3.6 percent and 2.9 percent, respectively. GOL/
Among energy stocks, Woodside Petroleum WPL.AX fell 0.9 percent snapping two days of gains, while Santos Ltd STO.AX shed nearly 2 percent.
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