The chief executive of German automaker says the current discussion regarding diesel cars is unjustified and that the diesel engine has a "great future" ahead.

"The diesels we are offering today are clean. They comply with the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) requirements and they meet the requirements and needs of our customers," Matthias Mueller, CEO of VW, told CNBC at the Frankfurt motor show.

Mueller explained that VW plans to continue to develop diesel cars, despite a global pushback against the technology by regulators and governments since the emissions scandal.

"There's going to be a co-existence between combustion engines and electrified drive systems over the next 10 to 20 years, so against this background we should all be patient and relaxed and leave the decision to our customers, they should decide which concept they prefer," he told CNBC during an interview recorded on Monday.

Volkswagen has been under pressure since the emissions scandal began in 2015. The car maker admitted that it used software to cheat U.S. and European regulators' tests from 2006 to 2015. This allowed the company to sell diesel-equipped vehicles without installing emissions control systems that could have affected performance or inconvenienced customers, according to U.S prosecutors.

Mueller added that he understood customer concerns regarding diesel engines and the possibility that diesel engines could be banned in the future. He said it is the responsibility of the car industry, as well as the electricity industry and the authorities to make sure bans are not implemented.