Volkswagen Group Australia has been hit with the first round of class action in the wake of the global emissions-rigging scandal, with a personal injury firm lodging documents with the Federal Court.
The case includes roughly 91,000 Australian owners of Volkswagen diesel cars that in   September were revealed to have been fitted with defeat devices, designed to cheat pollution tests.
With an average purchase price hovering around $50,000, the case could result in a refund worth up to $5 billion. 
Bannister Law filed two class actions on Friday. One was against Volkswagen Australia and the second was against Audi Australia, as they are two separate legal identities.
The Sydney-based firm's founder Charles Bannister said a part of the claim in each class action was that both VW and Audi guaranteed, under the consumer laws, the vehicles were fit for their purpose, and free from defects.
"In supplying cars containing the defeat device, the statutory guarantee was not complied with. If we're successful on that part of the claim, the customer may be entitled to a refund of the purchase price," he said.
"The other, alternative, damage or loss we're claiming is the reduction in the value of the vehicle, between what it would have been worth had this cheating software and excessive nitrogen dioxide emissions not been in the vehicle."
The boutique firm beat the rush of plaintiff law firms, including heavyweight Maurice Blackburn, to be the first to file a class action.
Despite the class action being the firm's first, Mr Bannister said its lawyers had the expertise and resources to run one given its specialisation in personal injuries, including motor vehicle accident claims.
He would not divulge a figure on how many affected customers had registered with the firm, simply describing it as "countless".
As the news broke, leading class action firm Maurice Blackburn Lawyers announced more than 7000 consumers had registered for its action, which will soon be filed.
"We are convinced that our action will offer thousands of aggrieved vehicle owners the best chance of success in holding the company to account and recovering some deserved compensation for them," said Damian Scattini, a principal at Maurice Blackburn 
Mr Bannister said about seven firms in the United Kingdom were considering class actions against the carmaker, and 30 had been launched in the United States.
"Reports are the company has allocated a fund of around $7 billion Euros to attempt to resolve worldwide class actions," he said.
In   October, Volkswagen Group Australia's managing director John White assured customers the affected cars were "technically safe" and fine to drive.
But Mr Bannister said: "It's not okay their car has been reduced through no fault of their own, and because they've been allegedly misled about what they thought they were buying and what they bought."
"It's also not okay these vehicles are potentially emitting far and in excess of the allowed nitrogen oxide emissions and would never have gained compliance under the Australian design standards and should never have been sold."
The German auto giant posted its first quarterly loss in 15 years last week. It subtracted $6.7 billion Euros from profit to cover the expense of recalling and repairing about 9 million cars in Europe and the United States equipped with the illegal software.
Volkswagen Group Australia told Fairfax Media it would be inappropriate to comment on impending legal matters.
"VGA understands this has been a difficult time and apologises for any disappointment and inconvenience felt by our customers, staff, dealers and partners," a spokesman said.
"VGA assures all its customers that the affected cars are technically safe and the necessary measures will be undertaken at no cost to them."