Mercedes-Benz was accused in a lawsuit Thursday of selling diesel cars in the US that spew excess emissions of nitrogen oxide and concealing the mechanism from regulators.

The class-action suit, filed in federal court in New Jersey by the Hagens Berman law firm, listed 14 vehicle models produced by Daimler unit Mercedes that are alleged to contain the emissions-cheating technology.

Representations by Mercedes that its BlueTEC diesel technology is the world's "cleanest" are "deceptive and false," said the suit.

"Mercedes has programmed its BlueTEC vehicles to turn off the NOx reduction systems when ambient temperatures drop below 50 degrees Fahrenheit," resulting in emissions 19 times US limits and, in some cases, as high as 65 times above the US environmental standard, the suit said.

Hagens Berman filed the case on behalf of a US Mercedes owner and seeks class-action certification to represent other owners of the cars.

A news release listed 14 Mercedes models with the "unlawful, unfair, deceptive and otherwise defective emissions controls" and urged owners to "contact Hagens Berman to find out your rights."

The suit likened the issue at Mercedes to the scandal which has enveloped German rival Volkswagen, which has faced a torrent of criticism and government probes after acknowledging that it installed "defeat devices" to flout emissions rules on some 11 million cars.

A Mercedes spokesman said there was no basis for the suit.

"Currently we are reviewing the documents and we will defend ourselves," said a Mercedes spokesman. "We believe the complaint is without merit."