* Italy to offer up to 6.75 billion euros debt on Wednesday
* To offer 30-yr bond for the first time since May 2011
* Yields are set to rise on three-year paper
By Francesca Landini
MILAN, Feb 13 (Reuters) - Italy will venture into ultra-long maturities at a debt sale on Wednesday, offering investors a reopening of a 30-year bond for the first time since May 2011 as the country readies for this month's national election.
The auction will give a hint of how foreign investors are responding to growing uncertainty over the Feb 24-25 ballot and will also test market appetite for long-dated debt ahead of the possible launch of a new benchmark.
Analysts expect yields to rise but believe the Treasury will draw decent demand, mainly from domestic investors, after profit-taking seen last week.
"While we remain positive in a medium term horizon, we think volatility will likely prevail in the near future," said Elia Lattuga, fixed income analyst at UniCredit.
Investors will take a cautious approach to Italy's debt until after the election, he added.
On Wednesday, Rome will offer up to 3.5 billion euros of three-year bonds and between 1 and 1.75 billion euros of 15- and 30-year bonds, together with five-year floating rate CCTEU certificates for a total planned amount of 6.75 billion euros.
The bond maturing on Dec. 1, 2015, was last sold at a mid-January auction at a yield of 1.85 percent, the lowest since March 2010. On Tuesday the three-year paper was trading around 2.38 percent, pointing to a rise in borrowing costs at Wednesday's auction.
The paper due on March 1, 2026 was changing hands on the secondary market at around 4.66 percent, while the bond maturing on Sept. 1, 2040, was hovering around 5.15 percent.
Borrowing costs for Italy and Spain jumped back up to mid-December levels last week after a strong rally at the beginning of this year, with analysts citing concerns over the economic impact of a strengthening euro.
"Peripheral countries are seen as the most vulnerable economies to the appreciation of the currency," said Chiara Manenti, fixed income strategist at Intesa Sanpaolo.
Market nervousness is compounded by growing uncertainty about the outcome of the election.
Final polls showed on Friday the center-left is on course to win despite a remarkable surge by Silvio Berlusconi, but is likely to have to form a governing coalition with outgoing premier Mario Monti.
"The road ahead is going to be bumpy for the Italian BTP," said Carlos Galvis, fund manager at Carmignac Securite. However, he said he still sees value in Rome's debt as soon as higher volatility is rewarded by higher returns.
Italy took advantage of the market rally last month to froantload its funding and is on track to met 18 percent of its total refunding needs with Wednesday's sale. (Additional reporting by Maria Pia Quaglia in Milan, editing by Gavin Jones, Ron Askew)