WASHINGTON — GOP lawmakers have subpoenaed the private e-mails of Labor secretary-nominee Thomas Perez, a possible sticking point ahead of his Senate confirmation hearing next week.

The subpoena, issued Wednesday by House Oversight Committee Chairman Darrel Issa, R-Calif., to the Justice Department, seeks the e-mails as part of an investigation into an agreement Perez brokered last year in his capacity as the nation’s top civil rights enforcer.

In the deal, Perez persuaded the city of St. Paul, Minn., to withdraw a lending discrimination lawsuit before it could be heard by the Supreme Court. In exchange, the Justice Department declined to join two whistleblower lawsuits against the city that could have returned millions of dollars in damages to the federal government.

Republicans have criticized the deal, which Justice Department officials say they reached out of concern the court might strike down their use of statistics in housing discrimination cases.