* BOJ injection underpins dollar/yen
* Dollar/yen outlook still negative
* Traders wary of possible BoJ action
* One-month dollar/yen implied vols spike (Updates prices, adds quote, more BoJ news)
By Gertrude Chavez-Dreyfuss
TOKYO, March 14 (Reuters) - The dollar rebounded from near-record lows against the yen on Monday, boosted by hedge fund buying as the Bank of Japan's huge infusion into money markets helped ease nervousness triggered by the massive earthquake and tsunami in northeast Japan.
The plunge in the Nikkei share average also prompted a sell-off in currencies that thrive when there is increased risk appetite, such as the Australian and New Zealand dollars .
The yen had advanced sharply on Friday on talk of repatriation flows as the disaster unfolded and was seen likely to extend gains especially if Japanese insurers try to raise funds by selling overseas holdings.
On Monday, the country was battling to prevent a nuclear catastrophe and to care for millions of people without power and water.
The greenback tumbled as low as 80.60 yen on electronic trading platform EBS, 1 yen away from a historic trough of 79.75 yen hit in 1995 . But news of the BOJ's offer to inject a record $183 billion into the money market helped the dollar pull away from the day's low. .
The BOJ also further eased its monetary policy on Monday and committed to increase the size of its fund pool for buying assets and conducting market operations backed by collateral by 5 trillion yen, to 40 trillion yen. .
"The force from monetary policy -- liquidity injections and increased risk of FX intervention -- will partially offset a temporarily more yen- supportive capital flow picture ," said Jens Nordvig, global head of G10 FX strategy at Nomura Securities International Inc in New York.
Overall, the bias on dollar/yen remains negative.
Crucial to dollar/yen's near-term direction is the size and financing sources for Japan's reconstruction. While there are no precise figures on the size of the country's reconstruction efforts, the source of financing is more straightforward.
Analysts said funding to rebuild Japan's tsunami-affected areas could come from a combination of public bond issuance or asset liquidation by Japanese insurance companies in overseas markets, moves that will likely strengthen the yen.
The dollar rose as high as 82.469 yen on electronic trading platform EBS, rallying from 80.60 yen , the lowest since early November. By mid-afternoon Tokyo trading the dollar was at 82.06 yen, up 0.2 percent.
Initial support this week is at 81.57, analysts at ActionForex.com said. A break of 81.57 yen would make a target 80.93 as the next support, and a subsequent breach of 80.93 would signal the resumption of a downtrend.
On the upside, analysts said there is minor resistance at 82.38 and a move above that would turn the pair's bias to neutral from negative. That would suggest that the sideways consolidation from 80.29 is still in progress.
In line with the steep fall in dollar/yen earlier in the global session, one-month implied volatility in the pair also spiked to a roughly four-month high at 11.75 percent , from Friday's 9.65 percent.
One-month 25 delta risk reversals, a barometer of risk sentiment, favoured dollar put/yen call options, suggesting increased bullishness on the Japanese currency. On Monday, dollar/yen risk reversals were quoted at 0.85/1.35 vols .
The euro also recovered 0.4 percent to 114.35 yen from a low around 112.62 yen .
A senior finance ministry official reiterated that Japan would take decisive measures on currencies if needed, when asked about the yen's strengthening against the dollar in the wake of Friday's devastating earthquake.
"The bottom line is it would be highly unlikely for Japanese authorities to allow dollar/yen to fall sharply today. So on that basis, it's going to be a nervy day but the downside is going to be limited for dollar/yen," said Greg Gibbs, strategist at RBS.
Meanwhile, the euro firmed against the dollar after European Union policymakers surprised markets over the weekend by reaching some significant agreements ahead of the March 24-25 heads of state meeting.
Essentially, the summit agreed to increase the lending capacity of the European Financial Stability Fund to its full limit of 440 billion euros and also lowered the interest rate charges for EFSF loans .
The euro was last at $1.3930 , up 0.2 percent on the day. Currency bid prices at 2:17 a.m. EDT (0617 GMT). All data taken from Reuters calculated from the levels at 4:30 p.m.(2030 GMT) in the previous New York session.
Last US Close Pct YTD Pct 2010
March 11 Change Change Close ------------------------------------------------------------- Euro/dlr 1.3935 1.3907 +0.20 +4.17 1.3377 Dlr/yen 82.070 81.890 +0.22 +1.13 81.150 Euro/yen 114.38 113.91 +0.41 +5.29 108.63 Dlr/swiss 0.9282 0.9292 -0.11 -0.57 0.9335 Stg/dlr 1.6070 1.6079 -0.06 +3.02 1.5599 Dlr/cad 0.9732 0.9715 +0.17 -2.36 0.9967 Aus/dlr 1.0082 1.0143 -0.60 -1.19 1.0203 Euro/swiss 1.2940 1.2926 +0.11 +3.62 1.2488 Euro/stg 0.8668 0.8646 +0.25 +1.12 0.8572 Nzd/dlr 0.7397 0.7430 -0.44 -5.06 0.7791 Dlr/Norw 5.5900 5.5943 -0.08 -3.98 5.8218 Euro/Norw 7.7933 7.7858 +0.10 +0.05 7.7895 Dlr/Swed 6.3325 6.3385 -0.09 -5.62 6.7098 Euro/Swed 8.8245 8.8210 +0.04 -1.74 8.9809 All spots Tokyo spots Europe spots Volatilities Tokyo Forex market info from BOJ World central bank news Economic Forecasts... Official rates... Forex Diary....... Top events........ Diaries........... Diaries Index........ Press Digests..... Polls on G7 economies.. European markets...... (Additional reporting by Ian Chua in Sydney; Editing by Michael Watson)