The audit examined more than 10,000 registered voters with data provided by the N.C. Division of Motor Vehicles and the U.S. Department of Homeland Security.
The state currently has more than 6.6 million registered voters, of which 30.4 percent are registered Republicans and 41.8 percent are registered Democrats.
Most recent polls indicate that the race between Democratic Sen. Kay Hagan and Republican Thom Tillis is close enough that a small number of votes could impact the results.
The N.C. Board of Elections has prepared instructions for election officials to challenge ballots of individuals on the list.
“We are working to ensure that no ballot cast by a non-citizen will count in this or any future election,” said Kim Westbrook Strach, executive director of the board, in a statement.
According to state law, challenged voters are scheduled to have hearings with the board to examine their qualifications to vote and will be notified of their hearings 10 days prior to trial.
If a hearing can’t be held before the election, the challenges will be heard prior to the next time the voter goes to the polls. Registering to vote in North Carolina as a non-citizen is a crime.