Handel's office sent the letters on Wednesday to the voters whose citizenship has been questioned. They should receive the letters this week telling them they may have to vote with a "challenged" paper ballot on Election Day.
Handel's office verifies citizenship for people who want to vote.
A three-judge federal panel ruled Monday that Georgia should have sought U.S. Justice Department approval before implementing a new process of using Social Security numbers and driver's license data to check voters' immigration status.
The panel ordered Handel's office to come up with a way of notifying people whose status has been questioned and allowing them to vote in some way on Election Day.