* TSX up 31.45 pts, or 0.3 pct, to 11,736.19 * Rebounds after hitting 2012 low at 11,555.08 * Materials rise on gold mining gains * Euro zone worries weigh on financials By Jon Cook TORONTO, May 9 (Reuters) - Toronto's main stock index turned positive on Wednesday as gold miners rallied after bullion prices rose from four-month lows, offsetting steep early losses as political turmoil in Greece heightened euro zone debt fears. Gold prices reversed course after hitting a low of $1,584.11 an ounce on Wednesday, helping Canada's heavily weighted materials sector rise 1.5 percent. After dropping sharply the past two days, Barrick Gold jumped 3.1 percent to C$37.86 and Goldcorp Inc was up 3 percent to C$35.43. Gold's move helped the Toronto Stock Exchange's S&P/TSX composite index halt its five-session losing skid. "Technically we're due for a bounce," said Barry Schwartz, vice president and portfolio manager at Baskin Financial Services. "Conditions are horribly oversold. These things tend to mean reverts." At 11:40 a.m. (1540 GMT), the Toronto Stock Exchange's S&P/TSX composite index was up 31.45 points, or 0.3 percent, to 11,736.19, rebounding after hitting a 2012 low at 11,555.08. Energy firms also halted their downward momentum, rising 0.4 percent on Wednesday. Oil and gas producers had tumbled after Brent crude prices slipped by over a dollar towards $111 a barrel on Wednesday. Encana Corp rose 2.6 percent to C$22.03 and Cenovus Energy was up 1.2 percent at C$32.59. Canada's top oil producer, Suncor Energy, was still down 0.7 percent at C$29.56. Political upheaval in Greece, a change in the French presidency and renewed concerns about the resilience of the Spanish banking sector sent markets tumbling overnight. Seven of Canada's 10 main sectors were lower. Losses were driven by a 0.4 percent drop in the heavyweight financial group. Canada's two largest banks led the losses, with Royal Bank of Canada falling 1 percent to C$53.55 and Toronto-Dominion Bank slipping 0.8 percent to C$79.76. Schwartz said Canadian stocks have been battered more than their global counterparts due to Canada's resource-heavy index and "high exposure" to gold and oil issues. "Our trading with Europe is limited, but it doesn't seem to matter," he added. Greece moved closer to a second snap election on Wednesday when the head of the biggest party launched a new attack on radical leftist Alexis Tsipras, saying his plans for a new government would push the country out of the euro zone.