German car manufacturer Daimler is to investigate its own emissions testing process.

The internal probe regarding its certification process in the US has been launched at the request of the Department of Justice.

The owner of Mercedes-Benz stated: “Daimler is co-operating fully with the authorities. Daimler will consequently investigate possible indications of irregularities and of course take all necessary actions.”

The news comes as the company has faced a class action case about its emissions which it dismissed as “baseless”.

It added in a statement: “The company’s experience with the US authorities has clearly shown that a conservative communication supports the constructive dialogue with the authorities. In addition the class actions are considered to be without merit and Daimler will defend itself against them with all available legal means.”

This week, Japan’s Mitsubishi Motors admitted falsifying fuel consumption tests in more than 600,000 cars.

It comes six months after the US Environmental Protection Agency said it would review diesel vehicles following an admission from Volkswagen that it installed software to cheat emissions tests.

According to analysts, Daimler’s shares have dropped by around 5% following the news.