A Civil District Court judge issued a temporary restraining order Thursday preventing the implementation of a major overhaul of the city’s hiring and promotional processes for classified employees, meaning those workers who have civil service job protection and are not at-will political appointees.

Judge Kern Reese’s order set Sept. 12 as the next day representatives of the city’s police and fire unions and the Landrieu administration will argue about whether the changes should be halted permanently. Civil District Court Judge Ethel Simms Julien will hear arguments then.

The changes are part of Mayor Mitch Landrieu’s “Great Place to Work Initiative,” introduced in April. The initiative proposed revisions to more than 30 civil service rules that together would give City Hall supervisors greater flexibility in hiring, evaluating, promoting and rewarding employees.

The changes are intended to ensure that the city can hire the best applicants for available positions and retain high-performing employees, Landrieu administration officials said.

But critics said the changes would leave the city’s hiring and promotional process open to discriminatory practices. They made their case Aug. 25 before the Civil Service Commission, which then voted 3-1 to approve the changes, with one commissioner abstaining.

The greatest source of division is the proposed elimination of the “rule of three,” which allows department heads and hiring managers to consider only the top three eligible candidates for a promotion or an open position, based on how they score on an aptitude test.

The administration said the rule eliminates from consideration qualified candidates who could be a better fit for a job based on characteristics other than having the highest test scores, such as additional years of experience.

Critics said dropping the rule would open the door to discriminatory practices and favoritism and might violate the state constitution.

The local chapter of the Fraternal Order of Police filed suit after the vote, challenging the commission’s action. The suit requested the temporary restraining order and temporary and permanent injunctions.

Claude Schlesinger, an FOP attorney, said he was “gratified” with Reese’s decision to issue the temporary restraining order.

Ted Alpaugh, another FOP attorney, described Reese’s order as “extremely important.”

“What could’ve happened was these rules could have been put into effect and they could have violated the state constitution,” Alpaugh said.

“The temporary restraining order will be in place until (Sept. 12). We look forward to making our case for these important reforms,” City Hall spokeswoman Garnesha Crawford said in response to a request for comment.

Follow Danny Monteverde on Twitter, @DCMonteverde.