The state auditor says state Treasurer Richard Moore and Lt. Gov. Beverly Perdue campaigned for governor using state resources on state time.
The reports from auditor Les Merritt's office came after several months of investigation, sparked by complaints from each candidate's opponent.
"I recognize that these allegations may be a political football, but as the independent State Auditor I have a statutory obligation to review any allegation of misconduct without respect to its motivation," Merritt said in a statement.
He said the investigation found that both campaigns used state computers and Internet connections "above a reasonable personal use" for their campaigns.
Auditors found that Perdue installed a separate Internet server and told staffers to use their personal computers during their lunch break for campaign work, but Merritt said she did not have adequate controls to ensure they did not.
They also found that a Moore staffer used her father-in-law's e-mail account to make public records requests about Perdue, while other staffers looked at political Web sites online and circulated campaign documents on work e-mails.