* Plans to increase yen bonds by 200 bln yen this FY
* Shift funds to bonds from stocks, to longer maturities
* May trim foreing bond holdings
* No plan to reduce full currency hedging on foreign bonds
* Will hold onto TEPCO bonds, expect full redemption (Adds quotes, background)
By Hideyuki Sano and Takefumi Ito
TOKYO, April 15 (Reuters) - Japan's Mitsui Life Insurance plans to increase its domestic bond holdings by 200 billion yen ($2.4 billion) in the financial year to March 2012 as it seeks to reduce risk exposure and in response to the regulatory environment, a senior executive said on Friday.
Japan's fifth-largest private insurer with total assets of around 7.5 trillion yen may trim its foreign bond holdings, primarily in the first half of the fiscal year, Akihiro Fujioka, head of the insurer's investment planning department, told Reuters in an interview.
The company has no plans to reduce its 100 percent currency hedging on the foreign bonds, Fujioka added.
"On the whole, we will continue to shift funds from stocks to bonds and within bonds, we will continue to shift to super-long bonds from short-term bonds," Fujioka said.
Fujioka said Mitsui expected the world economy to continue to grow modestly with limited inflation, helping the disaster-stricken Japanese economy to recover in the second half of the financial year that started on April 1.
But that has not changed the company's cautious investment strategy.
Mitsui and many other Japanese life insurers have been stepping up yen bond investment to match their long-term yen liabilities, thereby reducing their exposure to interest rate fluctuations.
Fujioka also cited new government regulations that took effect in April, which raise the risk weighting on stocks and other risky assets that insurers hold, as a reason behind shift to bonds.
As of last September, Mitsui Life held 2.863 billion yen of Japanese bonds as of September, nearly 70 percent of its securities investment. Its share holdings stood at 346 billion yen, about 8 percent of the total.
CURRENCY HEDGING
Fujioka said Japanese bond yields could rise a little as the government is expected to need to sell more bonds to finance its quake relief efforts.
"But investors like us, most of the life insurers, will continue to buy super-long bonds. So I'm not too worried about fiscal deterioration," he said.
Mitsui's foreign bond investments, which stood at 446 billion yen as of September, are fully currency-hedged and Fujioka said the company had no plans to change that stance unless there is a clear downtrend in the yen.
"There could be a moment when the dollar rises as high as 95 yen some time during the year. But there's still a risk that it could fall to around 80 yen," Fujioka said.
The dollar traded at 83.35 yen , having risen from a record low of 76.25 yen hit last month.
The company slightly increased its foreign bond investments in the year to March but it could trim its holdings in the current year as the cost of currency hedging -- short-term interest rates in the dollar and the euro -- has been rising on expectations of monetary tightening overseas, Fujioka also said.
Mitsui's foreign bond portfolio is roughly 60 percent dollar denominated and 40 percent euro.
Fujioka said he does not expect the debt crisis to hit Spain, though he added that the company holds German, French and Italian sovereign bonds but not Spanish bonds.
Fujioka also said the company held "not a big amount" of bonds issued by Tokyo Electric Power Co (TEPCO) , the operator of a crippled nuclear power plant and the country's largest issuer of corporate bonds.
Mitsui will keep holding these bonds as it expects them to be redeemed given the public nature of the power utility's business. ($1 = 83.510 Japanese Yen) (Reporting by Hideyuki Sano and Takefumi Ito; Editing by Chris Gallagher)