Volkswagen AG chief executive Matthias Mueller is hopeful the German auto maker can reach an agreement with the US government by the end of the year on the size of a fine to settle a criminal investigation of the company's alleged violations of clean air laws.
Mueller, speaking on the sidelines of the Paris auto show on Wednesday, said he also saw "good progress" towards an agreement with US regulators that could allow Volkswagen to repair certain 3.0-litre diesel engines that emit more pollutants than US law allows.
Speculation the US Justice Department will demand a multibillion-dollar fine to settle a criminal investigation of the automaker's use of illegal software to deceive US environmental regulators sent Volkswagen shares into a tailspin this week.
Mueller told reporters "we have been in a constructive dialogue with authorities in Germany, in Europe and the US for the past 12 months", and said he hoped to know the results of all the investigations "in the foreseeable future".
A Justice Department spokesman declined to comment.
Reuters reported in August that Volkswagen and the US Justice Department have held preliminary settlement talks about resolving a criminal probe into the automaker's diesel emissions scandal, citing two sources briefed on the matter.
The talks have continued in recent weeks but it is not clear when a settlement will be reached.
Earlier in September, a Volkswagen engineer pleaded guilty to one count of conspiracy in connection with the diesel emissions cheating case, and said he will cooperate with the Justice Department investigation.
VW in June agreed to pay up to $US16.5 billion ($A21.4 billion) to resolve civil litigation related to the emissions cheating.
The company agreed to buy back vehicles if they could not be repaired as required by US and California regulators, and to fund projects such as expanded electric vehicle charging networks.
Mueller said he was concerned about the size of potential additional fines.
"The settlement that we have ... reached with the civil authorities isn't cheap," he said.
"We have made provisions for everything that we believe we will have to face, including fines, environmental projects, compensation to the people ... We will have to see if that's enough or not."
Volkswagen has set aside 17.8 billion euros ($A26 billion) to pay for costs related to the global emissions cheating scandal.
The company faces civil litigation and potential fines from government regulators in the EU and other markets around the world.
Mueller and Volkswagen global brand chief Herbert Diess said the company is not ready to abandon diesel technology, and could continue to offer diesel models for the US market.
"At some point there will be a tipping point, where electric mobility will gain the upper hand. I don't know when this will be. Maybe 2030 or 2035," Mueller said.
Volkswagen executives are using the Paris auto show to tout its future electric vehicles, aiming at US electric car maker Tesla Motors Inc.
