Washington (CNN) -- Officials with the Justice Department are scheduled to meet Tuesday with Sheriff Joe Arpaio of Maricopa County, Arizona, as they look into alleged civil rights violations.
Last week, the department gave the sheriff's lawyers until Tuesday to turn over documents and cooperate with their inquiry.
Authorities are investigating whether Arpaio's policies and law enforcement sweeps discriminate against Hispanics.
Arpaio, who has called himself "America's toughest sheriff," is known for his hard-nosed opposition to illegal immigration.
Detractors accuse him of discriminating against Hispanics, while supporters say the Justice Department's civil rights probe and its separate criminal investigation are politically motivated.
If the sheriff's lawyers don't turn over the documents, the government has threatened to sue the sheriff's office "to compel access to the requested documents, facilities and personnel," Assistant Attorney General for Civil Rights Thomas Perez has said.
For their part, Arpaio's lawyers reject claims that he is uncooperative. The attorneys contend the Justice Department may not require documents simply to see if they can find something to support their suspicions of discrimination.
CNN's Terry Frieden contributed to this report.