* TSX rises 3.44 points, or 0.03 percent, to 12,847.52 * Seven of the 10 main index sectors decline * Brookfield Office Properties jumps on takeover deal * SNC-Lavalin climbs after plan to sell AltaLink stake * Petrominerales soars 51 percent on Pacific Rubiales bid By John Tilak TORONTO, Sept 30 (Reuters) - Canadian stocks were little changed on Monday as a jump in Brookfield Office Properties helped offset broad market weakness fueled by worries about the congressional budget impasse that threatened to paralyze the U.S. government. Shares of Brookfield Office Properties jumped 14.1 percent after parent company Brookfield Property Partners said it would buy the 49 percent of Brookfield Office that it did not already own to consolidate their office property portfolios. Also dampening investor sentiment was political uncertainty in Italy, where some senators from Silvio Berlusconi's center-right party looked ready to form a breakaway group unless the former premier backed down on his hard line to bring down Italy's government and head to elections. As a midnight shutdown deadline approached, Democrats who control the U.S. Senate appeared confident that they would defeat Republicans' efforts to delay "Obamacare" health reforms, which would enable them to send a "clean" funding bill back to the House of Representatives for a vote. "It's politics impinging on capital markets, in a negative way," said David Cockfield, managing director and portfolio manager at Northland Wealth Management. U.S. politicians are playing to their home crowds, he added. The Toronto Stock Exchange's S&P/TSX composite index was up 3.44 points, or 0.03 percent, at 12,847.52. In comparison, U.S. stocks were down sharply, and the TSX looked set to outperform the S&P 500 in the third quarter. The Canadian index will do better than its U.S. counterpart in the fourth quarter as well, said Cockfield, who expects the TSX to end the year at 13,500. Seven of the 10 main sectors on the index were in the red on Monday. Tracking a drop in the price of oil, shares of energy producers shed 0.8 percent. In the group, Suncor Energy Inc was down 1.2 percent at C$36.87, and Canadian Natural Resources Ltd gave back 0.6 percent to C$32.24. Financials, the index's most heavily weighted sector, added 0.2 percent, with declines in insurance companies offset by gains made by banks. Manulife Financial Corp fell 0.9 percent to C$17.22, while Royal Bank of Canada advanced 0.2 percent to C$66.66. Gold-mining stocks eked out a small gain, with Goldcorp Inc climbing 1.8 percent to C$27.02 and Barrick Gold Corp adding 0.4 percent to C$19.18. SNC-Lavalin Group jumped 2.7 percent to C$42.48 after the engineering and construction company said it was looking to sell an equity stake in AltaLink, Alberta's largest regulated electricity transmission company. Shares in Canadian oil company Petrominerales soared about 51 percent to C$11.71 after a takeover deal by Pacific Rubiales, Colombia's largest private oil producer.