The federal government has granted Florida election officials access to a database of noncitizen residents for use in Republican-backed efforts to remove people who are not American citizens from voter registration rolls.

The decision by the Department of Homeland Security, which came after efforts by the Obama administration to block access, was issued in a letter to Gov. Rick Scott’s administration and made public on Saturday. Mr. Scott, along with the state’s Republicans, had been pushing for months to gain access to the database, which is maintained by the department, arguing that it would allow for a more accurate review of voter lists.

The decision could give a boost to what has become a broad push by Republicans in several states to prevent voter fraud by expunging what they say are thousands of ineligible noncitizens from voter lists.

Opponents of the Republican effort, who recognize that people who are not American citizens have no right to vote, have argued that the federal database, the Systematic Alien Verification for Entitlements, or SAVE, was never intended to be used for purging voter lists. They have also charged that the purge could violate voters’ rights laws and be used to discriminate against minorities. With so little time left before elections, they argue, anyone wrongfully purged could be barred from voting anyway.