FRANKFURT: Munich, home to German carmaker BMW, is considering banning diesel vehicles because of "shocking" nitrogen oxides emissions in the Bavarian capital, its mayor told a newspaper on Wednesday.

The scandal over rigged diesel emissions tests at German carmaker Volkswagen has thrown the engine technology into doubt and has highlighted carmakers' struggle to comply with ever stricter rules capping nitrogen oxides emissions.

"As much as I would welcome avoiding such bans, I think it is just as unlikely that we can continue to do without bans in the future," Munich mayor Dieter Reiter was quoted as saying by Sueddeutsche Zeitung on Wednesday.

Asked about the latest nitrogen oxide readings across the city, he said: "The results are shocking, nobody expected this."

The city of Stuttgart, home of Mercedes-Benz and Porsche, is preparing to keep the city free of some vehicles from next year.

Between 133,000 and 170,000 vehicles could be affected by a ban in Munich, depending on how strict it will be, the paper said. Cars meeting the latest Euro 6 emission rules would be exempted, it added.

While only a niche market in the United States, about half the new cars sold in Germany ran on diesel engines before the VW scandal broke, though diesel market share has since declined.

Due to strong diesel demand in their home market, given the technology's fuel efficiency, Germany's three major carmakers have traditionally spent heavily on diesel plants and development.

The prospect of diesel bans is seen as weighing on the used vehicle market. Carmakers' leasing and vehicle financing divisions rely on stable used vehicle values because car loans are backed by the value of the underlying vehicle.