The Metropolitan Transportation Authority should sell the roof over its head before raising fares on New Yorkers twice in one year, Council Member Eric Gioia said yesterday.

Mr. Gioia, a likely candidate for public advocate in 2009, is calling on the MTA to sell off the 20-story building it owns at 44th Street and Madison Avenue to raise the money necessary to avert a fare increase.

“There’s no justification for the MTA to be on Madison Avenue,” Mr. Gioia, of Queens, said at a press conference in front of the building yesterday. “This is a glaring example of an asset being underutilized.”

He estimated that the property, which contains more than 230,000 square feet of prime office space, could fetch “at least” $200 million on the open market. Mr. Gioia suggested that after the sale, the MTA should move its offices to Queens.

A spokesman for the authority, Jeremy Soffin, said selling 347 Madison Ave. is not under consideration at present but that the MTA has sold large properties in the past.

“The MTA has assessed its real estate assets and sold a number of properties to support public transportation, including the billion-dollar sale of the West Side Yards. Just as importantly, we are cutting costs by 6 percent, consolidating back office functions and integrating our bus companies to save money,” Mr. Soffin said via e-mail. “We do not have plans to sell office buildings currently required for MTA use.”

Earlier this year, the MTA raised the price of an unlimited one-month MetroCard to $81 from $76 and of a one-week unlimited MetroCard to $25 from $24.

MTA officials said recently that another fare hike may be necessary to meet a growing deficit of as much as $700 million next year due to declining tax revenues and rising fuel prices.