Law firm Maurice Blackburn is preparing to launch a new set of class actions covering 3.0 litre V6 diesel versions of the Porsche Cayenne, VW Touareg and several Audi models, in addition to a separate class action lawsuit launched in mid-  November on behalf of about 13,000 owners of Volkswagen, Skoda and Audi vehicles. 
Maurice Blackburn principal Jason Geisker said on Friday the proposed new class actions came after two United States authorities announced that all of the 3.0 litre diesel models contained prohibited defeat devices and exceeded maximum permitted nitrogen oxide emissions.
Those rulings were made by the United States Environmental Protection Agency and the Californian Air Resources Board.
Mr Geisker said the new information from the US authorities about the impacted 3.0 litre V6 diesel vehicles was likely to increase the total number of Australian vehicles affected by what the law firm calls "Dieselgate", to in excess of 100,000 vehicles.
Mr Geisker said it was shaping as one of Australia's largest consumer class actions.
The law firm said anyone with a Porsche Cayenne 3.0 litre diesel model from 2013 to 2016, and 2013-2016 VW Touareg was eligible to sign up for the class action. A number of 3.0 litre diesel Audi models were in the same category. They comprise the 2009-2016 Audi Q5, the 2009-2016 Audi A6, and the Audi Q7, A7 and A8 models from 2009 to 2016.
Volkswagen is embroiled in a highly-damaging global recall scandal after tests showed that tens of thousands of vehicles had been fitted with devices designed to mask the level of emissions.
Early in   November, boutique law firm Bannister lodged documents for class actions in Australia against Volkswagen Australia and Audi Australia, separate to the Maurice Blackburn actions.