* Nikkei and Topix both rise 0.6 pct * Exporters still benefit from LDP victory * Investors take profit on utilities after Monday's rally By Dominic Lau TOKYO, Dec 18 (Reuters) - Japan's Nikkei share average advanced on Tuesday, extending the previous session's gains after the conservative Liberal Democratic Party won a landslide election, although investors took profit on power companies. The Nikkei rose 0.6 percent to 9,882.68 in mid-morning after gaining 0.9 percent to its highest close in 8-1/2 months on Monday. Tuesday's gain took the benchmark deep into "overbought" territory, with its 14-day relative strength index at 79.7, well above 70 which is deemed overbought and often indicates a possible near-term correction. The Nikkei also broke above the upper band of the Bollinger Bands, a short-term momentum indicator, also signalling a possible pull back in the short-term. "At this stage we've seen some profit-taking in utilities after a huge move they made yesterday. The yen-sensitive, LDP-trade is still in full effect, with volume remaining very good considering the quiet period of the year," a senior dealer at a foreign brokerage said. "It's not as aggressive as yesterday but certainly nothing to sneeze at. We wouldn't be surprised to see profit-taking a little bit more than we are currently seeing." The benchmark Nikkei has risen 14.1 percent over the past month, driven by the yen weakness after Shinzo Abe, who was elected as the new prime minister on Sunday, called for the central bank to undertake "unlimited easing" and set an inflation target of 2 percent. Expectations that Washington will be able to resolve the 'fiscal cliff' -- a combination of spending cuts and tax increases taking effect in the new year -- also added to the positive mood in the market. Exporters and real estate firms, which benefit from a weaker yen and Abe's call for reflationary policy, extended gains on Tuesday. Among the exporters, Honda Motor Co, Canon Inc , Hitachi Ltd and Toshiba Corp were up between 0.7 and 1.3 percent, while the real estate sector added 0.9 percent. The broader Topix index gained 0.6 percent to 812.84. Power utilities fell after rallying on Monday following the LDP victory as the party is opposed to nuclear-free policy. Kansai Electric Power Co lost 4 percent and Chubu Electric Power Co dropped 2.4 percent, but Tokyo Electric Power Co, which were battered by a meltdown in its Fukushima nuclear power plant after last year's earthquake, surged 21.3 percent. TEPCO was the most traded stock on the main broad by turnover, while Kansai Electric Power was the fourth-most traded.