NEW ORLEANS — Days before a federal judge will hear arguments about whether he should approve a consent decree between the U.S. Department of Justice and the Orleans Parish jail, Sheriff Marlin Gusman and Mayor Mitch Landrieu launched attacks on each other’s plans to pay for or avoid paying for changes the court order would mandate.

Landrieu warned Thursday that layoffs of police and firefighters, cuts to city services, furloughs of other employees and higher taxes could be necessary if the city is forced to simultaneously pay for separate consent decrees for the New Orleans Police Department and the Orleans Parish Sheriff’s Office.

Sheriff Marlin Gusman shot back a short time later, accusing Landrieu of using “scare tactics” in an effort to avoid paying for something he said the city is responsible for.

Landrieu made his comments during an emergency meeting of the City Council that he called on Wednesday.

He said that the city does not have enough money to pay for jail improvements Sheriff Marlin Gusman has agreed to make under a consent decree with the Justice Department. That proposed agreement is pending approval in federal court.

Meanwhile, a five-year, $55 million consent decree involving the NOPD has already been approved. Landrieu and Chief Administrative Officer Andy Kopplin said the city made all the cuts it could for the 2013 budget to fund that consent decree, while avoiding layoffs or cuts to city services.

Since the NOPD consent decree was approved, Landrieu has sought to back out of it. A federal judge has denied that request, something the city is now appealing.

Landrieu said Thursday that the OPSO consent decree could cost up to $22 million a year for five years for a total of $110 million. That, he said, is something the city cannot afford. Still, he noted, the bill will be sent to City Hall since the city must pay for the jail even though it does not operate it.

“It does not make sense to lay off or furlough police officers or firefighters so we can hire more prison guards and pay them higher salaries,” Landrieu said.

Speaking later in the morning, Gusman disputed the cost figure the city cited but would not provide an estimate for what the consent decree would cost.

“I have no idea where he got that from,” Gusman said. “It’s not $22 million; it’s not even close to that.”

Ryan Berni, a spokesman for Landrieu, said the city’s figure came from conversations with the Justice Department, which told the city that information came from the Sheriff’s Office.

Gusman spent the majority of his news conference firing back at Landrieu, saying that the mayor has delayed changes at the jail by refusing to pay for them.

“Today’s City Hall spectacle is a last-ditch attempt by the mayor to deflect attention away from a problem that he knew was coming for many years,” Gusman said. “I’m insulted by the mayor’s lack of leadership, his distortion of the facts and scare tactics. The city is failing in that legal commitment, and they know it.”

For decades, the NOPD has been faced with claims of corruption, civil rights violations and even murder. At the same time, the Orleans Parish jail also has been under fire for claims of civil rights violations, abuse of prisoners by deputies and other inmates and inadequate medical services.

U.S. District Judge Lance Africk is scheduled to begin a week of hearings on the OPSO decree Monday. Those hearings will be used to discuss how the changes will be paid for if the court approves them.