* Yen weakness likely to support market this week - analyst
* Nissan sags on disappointment with earnings
By Ayai Tomisawa
TOKYO, Feb 12 (Reuters) - Japan's Nikkei share average climbed 2.6 percent on Tuesday, boosted by exporters as the yen weakened after a U.S. Treasury official voiced support for Japan's aggressive policies to combat deflation and bolster growth.
The index rose to 11,445.77, within reach of a 33-month high of 11,498.42 struck last Wednesday. The benchmark has risen nearly one-third since mid-November.
Japan's aggressive expansionary monetary policies have sharply weakened the yen in recent months, prompting concerns in Europe and the United States.
With finance ministers from the Group of 20 nations scheduled to meet this week, investors betting on a weaker yen were relieved after U.S. Treasury Undersecretary Lael Brainard said the United States supports Japanese efforts to end deflation and reinvigorate growth.
"Her comments gave confidence to the market. It was surprising, and was taken as the Obama administration giving a green light to 'Abenomics'," said Takuya Takahashi, a market analyst at Daiwa Securities.
The dollar touched a high of 94.42 yen on Monday, its highest level since May 2010.
Exporters gained ground, with Toyota Motor Corp rising 2.8 percent, Sony Corp advancing 2.9 percent and Canon Inc adding 2.6 percent.
Nissan Motor Co lost ground, however, falling 2.0 percent after it bucked the optimistic trend among other Japanese carmakers reporting quarterly earnings, leaving its annual profit forecast unchanged as sluggish sales weighed on its bottom line.
Financials were also in demand on hopes that the rallies would energise share trading and bolster their commission income, with Nomura Holdings soaring 4.4 percent and Daiwa Securities Group jumping 4.8 percent.
"Investors were worried that finance ministers would criticise the recent weakness in the yen. While the currency moves have been sensitive to officials' comments in general, people thought any comment from G20 would trigger yen buying," said Hiroichi Nishi, an assistant general manager at SMBC Nikko Securities. "But such worries are receding as she (Brainard) said she supports Japan's efforts to end deflation."
European Central Bank council member Jens Weidmann also said the euro was not overvalued at current levels.
Analysts said that concerns over the euro-zone economy, which dented the market sharply on Friday, are receding for the time being.
They added that the yen is expected to stay under pressure on expectations that Prime Minister Shinzo Abe will endorse a far more dovish Bank of Japan regime when the current leadership's term ends next month.
The BOJ is expected to refrain from taking fresh easing steps when it meets this week.
"The Nikkei is expected to stay strong this week and may hit 11,500 if the yen weakens further," said Daiwa's Takahashi.
The broader Topix gained 2.0 percent to 976.19.