Volkswagen Ireland has pledged to inform up to 80,000 Irish drivers of diesel-engined, Volkswagen, Audi and Skoda and Seat as to whether their vehicles need to be re-fitted to remove software used to distort diesel emission readings.

In a statement, VW Ireland said it was still working with its various factories to establish the exact numbers affected in each local market.

Once regulators approve the technical fix required, car owners will be invited to make an appointment with a mechanic to have the software removed.

The Volkswagen Group confirmed yesterday it would present exact numbers affected worldwide and the technical fix required to regulators during October, and that all local franchises would set up national information websites.

The group has also appointed the US law firm Jones Day to investigate how the emissions cheating occurred.

Germany is reported to have broadened its investigation into the car emission-cheating scandal to include Audi.

Wolfram Herrle, chief prosecutor in the region where Audi is based told German media that a preliminary investigation had been launched into the company's conduct.

"We are currently reviewing all the facts in order to decide whether an investigation should be initiated," he said.

Audi has previously said the 2.1 million of its cars were affected by the diesel scandal, including the A1, A3, A4, A5, A6, TT, Q3 and Q5.