A class action that could top $100 million has been launched in the Federal Court on behalf of the owners of more than 90,000 VW, Audi and Skoda diesel vehicles that were fitted with devices to cheat emissions tests.

The owners said the vehicles are now "lemons" and have little or no value.

Alistair Dalton, a lead applicant in the class action, had been a loyal VW customer for decades.

"The Volkswagen brand's always been very big in my eyes," he said.

"My very first car was a Volkswagen Beetle back when I was a teenager and that's one of the reasons why... I did purchase a Volkswagen."

Mr Dalton said he lost faith in Volkswagen after the company admitted installing emissions test defeat devices in 11 million diesel vehicles worldwide.

His family owns two diesel VWs.

"I feel that I've been lied to," he said.

"I own those two vehicles, I own them outright."

Maurice Blackburn Lawyers principal Jason Geisker said there is a lot of anger from motorists who feel betrayed.

"Every day in normal use, these vehicles are spewing out nitrous oxide, poisonous gases into the environment at far beyond levels that are permitted under Australian law or European law."

Mr Geisker said it is not an easy fix.

"It's not just a question of a change of a software program and the aggrieving thing about this action is Volkswagen themselves have not worked out what to do to fix it yet.

"And that's why this whole situation is unsatisfactory."

Volkswagen, the world's biggest car company by sales, owns the Skoda brand too.

Steven Roe bought a Skoda diesel in 2012 because of its low emissions.

He did not know its test results were rigged.

"I believe now that because of what's happened, that vehicle will be virtually worthless," he said.

"It's a total lemon."

Audi is another big selling brand of the Volkswagen group.

Robyn Richardson bought her diesel Audi believing it would be better for the environment.

"I made the decision to buy my, what I now know is a dirty diesel, on the basis of the trust I held in the company that what I was getting was essentially the next best thing to a hybrid," she said.

Volkswagen US offers gift cards to owners

The Volkswagen parent company has set aside nearly $10 billion to cover costs and in the United States, unhappy owners are being buttered up with gift cards.

Volkswagen Group of America said 20,000 owners of diesel cars that have violated US emission standards will receive $500 gift cards, plus $500 to help pay for vehicle repairs.

Volkswagen America said accepting the gift cards does not prevent owners from filing lawsuits.

Volkswagen Group Australia has not responded to the ABC's request for comment.