The hospital's response was due June 14, 10 working days after the officials' receipt of the letter, said Jim Jones, media representative for the Department of Health and Human Services.
Hospital officials met last week to prepare a plan of action in response to deficiencies identified by the health department.
The details of the deficiencies will not be released until DHHS has reviewed the hospital's plan of action.
Tom Hughes, a spokesman for UNC Hospitals, said he was not sure why the hospital's response had not been sent on time.
He said he anticipated that the response would be sent to DHHS this week.
Kathryn Chappell, director of risk management for UNC Hospitals, is in charge of creating the response to the deficiencies.
Hughes said Chappell was the only person who knew about the status of the response.
Chappell was out of town and could not be reached for comment.
Jones said he is not sure if there is a penalty for late submission but that someone from DHHS would be calling UNC Hospitals to urge them to send the response.