A federal judge in California overseeing more than 500 lawsuits filed against German automaker Volkswagen AG over its excess diesel emissions on Monday said he planned to name a former FBI director to help settle the cases.

U.S. District Judge Charles Breyer said he would name Robert S. Mueller, former director of the FBI, as "settlement master" in the VW lawsuits.

Mueller, a Washington lawyer, will "use his considerable experience and judgment to facilitate settlement discussions among the various parties in these complex matters," Breyer wrote on Monday.

Breyer said the need for a settlement adviser was "urgent" and will give VW and lawyers for all sides until Jan. 15 to object to the appointment.

VW potentially faces billions of dollars in claims from owners of vehicles with excess emissions. Separately, the Justice Department sued VW last week under the Clean Air Act seeking up to $46 billion.

VW has admitted to using software to allow 580,000 vehicles to emit up to 40 times legally allowable pollution. It also faces investigations by 47 state attorneys general.

Breyer said there are "few, if any, people with more integrity, good judgment, and relevant experience" than Mueller. Breyer said Mueller is "uniquely qualified to work with and earn the trust of the parties, including the consumer and car dealer plaintiffs, the United States government, the Volkswagen defendants, and the interested state governments."

Last month, VW named its own adviser, lawyer Ken Feinberg, to create a VW diesel owner claims program. Feinberg said the program is aimed in part at settling lawsuits out of court.

Volkswagen of America Chief Executive Officer Michael Horn said Monday the goal of hiring Feinberg is to help customers. "Everything is quicker, less hassle, they get the money faster," Horn said.

VW hasn't decided the details of the compensation program or on remedies, including potential vehicle buybacks.