Lawmakers still fighting over whether February’s economic stimulus law is working will soon face a new dilemma: whether to extend some of the act’s tax breaks or let them expire.

Several popular pieces of the American Recovery and Reinvestment Act are scheduled to disappear by the end of 2009 at the latest.

For example, the $8,000 first-time homebuyer tax credit that home builders and real estate agents are touting does not apply to purchases finalized after Nov. 30.

A deduction for state and local sales and excise taxes on the purchase of a new car or SUV costing up to $49,500 expires Dec. 31.

So does an exclusion from taxable income for the first $2,400 in unemployment compensation.

And a health insurance subsidy — 65 percent of the premium for nine months of COBRA coverage for laid-off workers — applies only to those who lose their jobs before the end of this year.

Over the past week, as part of his campaign for health care legislation, President Obama has been touting the health premium subsidy. But even with the unemployment rate above 9 percent, the administration has not taken a position on whether this subsidy and other expiring provisions should be continued into 2010. A Treasury Department official said the administration is still studying the effectiveness of the programs.

A House Democratic leadership aide sounded a similar note.

“The tax provisions put in place by the Recovery Act were emergency, temporary items to deal with the immediate economic crisis,” the aide said. “There has been no discussion at this point about whether or not it will be necessary to extend these provisions.”

That review will begin after Labor Day, when members return from their August recess. There is significant support for extending the special breaks, but concerns about the soaring federal deficit could make the decision a tough one.