Sen. Charles Schumer said Monday he will seek to extend a tax credit for mass-transit commuters set to expire at the end of the year.

In a news conference in Grand Central Terminal, Schumer said letting the employer-based tax break lapse would cut the benefit to transit commuters to $130 per month from $245, which is the tax deduction currently offered to commuters who drive to work.

"It is unfair to say those who use a train or bus to work should not get the same deduction" as drivers, Schumer said. "They're doing the same thing: leaving their homes, going to work."

The benefit lets employees deduct up to $245 in mass-transit commuting costs a month from their gross income. That would be enough to cover a monthly MetroCard or, for suburban commuters, most of the cost of taking Metro North and Long Island Rail Road into the city.

In the New York metro area, there are 700,000 mass-transit commuters' who benefit from the tax deduction, for a total of $330 million this year, according to WageWorks, an employee benefits company. Schumer said he would tie the mass-transit tax break to a bill that extends a host of other benefits.