SHANGHAI, May 28 (Reuters) - Shanghai copper extended gains on Monday, as risk aversion eased after surveys showing Greece's pro-bailout camps leading opinion polls helped calm fears of a disorderly exit from the euro bloc.
But investors are expected to stay cautious as European politicians bicker over whether to issue euro bonds and as Spain struggles to manage its highly indebted banking sector.
The most-active September copper contract on the Shanghai Futures Exchange rose 0.9 percent to 55,870 yuan ($8,800) a tonne, after closing up 0.4 percent in the previous session. Shanghai copper prices have shed more than 4 percent so far this month.
The London Metal Exchange data on Thomson Reuters screens is not updating due to an issue with the real-time data feed from the exchange. The issue is currently being investigated, according to an official with the exchange's help desk.
Surveys showed on Saturday Greece's conservatives have regained an opinion poll lead that would allow the formation of a government committed to keeping the country in the euro zone.
Central banks and companies risk making a grave error if they do not brace for a possible Greek exit from the euro zone, Belgium's foreign minister said on Friday, rattling markets already alarmed by Spain's deteriorating finances.
German central bank chief Jens Weidmann dismissed French-backed calls for the use of euro bonds to boost economic growth in Europe, saying in an interview in French newspaper Le Monde that "this debate irritates me a bit".
Portugal is wrongly following a policy of "austerity at any price" and will need at least an extra year to reduce its budget deficit to the target established under a 78 billion euro ($98.1 billion) bailout, the leader of the opposition Socialists said.
In the United States, consumer sentiment rose to its highest level in more than four years in May as Americans stayed positive about the job market, while higher-income households were optimistic on wage increases, a survey released on Friday showed.
Asian shares and the euro edged up from lows on Monday after surveys showed a lead in opinion polls for Greece's pro-bailout camps.
The survey also helped the euro bounce off two-year lows in early Asia trade on Monday.
Base metals prices at 0134 GMT
Metal Last Change Pct Move YTD pct chg
SHFE CU FUT SEP2 55870 500 +0.90 0.43
SHFE AL FUT SEP2 16030 05 +0.03 1.20
HG COPPER JUL2 347.65 2.85 +0.83 1.18
SHFE ZN FUT SEP2 14930 140 +0.95 0.91
SHFE PB FUT 15200 45 +0.30 -0.59
Shanghai and COMEX contracts show most active months
($1 = 6.3439 Chinese yuan)