Rome, Oct 3 (IANS): The Italian antitrust authority has opened an investigation into Volkswagen (VW) for possibly misleading consumers who have bought diesel cars from the German automaker.

The inquiry into VW and its subsidiary in Italy is launched because of "complains filed by a number of consumer associations", Xinhua news agency quoted antitrust authority as saying in a statement released on Friday.

The hypothesis for investigating concerned a possible "improper commercial practice in selling cars and commercial vehicles with qualities and emission standards that would actually be below the declared values," the antitrust body said.

At least 648,458 vehicles were overall involved in the scandal in Italy, according to data released by VW earlier this week.

They will all be recalled to undergo revision.

The Italian antitrust body said its investigation against improper commercial practice would concern "several types of vehicles sold by VW Group between 2009 and 2015, with VW, Audi, Seat, and Skoda brands."

"Consumers may have been misled in their purchases by the claims on emissions and type approval standards used by Volkswagen within their advertising campaigns and informational brochures distributed by dealers and retailers," it added.

Last month, VW acknowledged cars with Type EA 189 engines had been equipped with a device able to temporarily reduce emissions during official testing in the US and Europe.

The cheating practice involved up to 11 million diesel cars worldwide, the company admitted.