WASHINGTON — The Obama administration has hired a credit reporting agency to help verify the incomes of people who apply for federal subsidies to buy insurance under the new health care law.

The company, Equifax Workforce Solutions, a unit of Equifax Inc., will provide information that is more current than what is available on federal income tax returns.

The use of a commercial information vendor comes as Congressional Republicans are expressing concern about the administration’s ability to verify data in subsidy applications. Subsidies, in the form of tax credits, will be available to millions of low- and moderate-income people who are not eligible for Medicaid and have not been offered affordable coverage by employers.

The White House announced on July 2 that it was delaying until 2015 a major provision of the health care law that requires larger employers to offer health coverage to employees and to report such coverage to the Internal Revenue Service. The subsidies, averaging more than $5,000 a year per person, will be available through marketplaces, or exchanges, where consumers in every state can shop for insurance, starting Oct. 1.