Koskinen, speaking Wednesday at the National Press Club in Washington, drew on his experience a decade ago as the deputy mayor of the city government in the nation’s capital. Even as the IRS faces budgetary pressures, he said, according to prepared remarks, the health law will be a priority, just as snow removal is essential for a city.

Starting with the tax returns that will be filed in early 2015, the IRS will be responsible for enforcing the individual mandate to purchase health insurance and ensuring that people claim the correct amount of subsidies for insurance.

Koskinen, 74, became commissioner of the U.S. tax agency last year. He said the health-care law gives the IRS a chance to regain credibility, which suffered last year when the agency revealed that it had given small-government groups extra scrutiny because their names included the words Tea Party.