Governments, investors and car owners around the world are gaining ground in efforts to pressure Volkswagen AG
(VLKAY) for settlements over its emissions-cheating scandal, aiming for terms similar to a $15 billion U.S. agreement.

From Australia to South Korea to Ireland, governments and consumers are ratcheting up legal and regulatory demands in part because such moves in the U.S. yielded a speedy shift to contrition from combativeness.

In many of the countries where Volkswagen still faces legal action, it is arguing the so-called defeat device on its diesel engines wasn’t illegal or the car emissions didn’t violate local rules, according to court records and documents reviewed by The Wall Street Journal.

If the efforts succeed, the costs to resolve the diesel scandal could rise well beyond the €18.4 billion ($20.5 billion) the company has set aside. Of the roughly 11 million vehicles affected by Volkswagen’s yearslong effort to cheat on diesel emissions standards, about 10.4 million are outside the U.S.

While outcomes are still unclear, the company’s position has been chipped away by recent decisions. In Germany, the cost could rise as much as €4 billion following a ruling earlier this month by a court in Braunschweig, near Volkswagen’s headquarters. The court said it would address more than 170 suits filed by hundreds of Volkswagen investors who allege the company failed to quickly inform them of the diesel probe. Volkswagen has rejected the allegation.

Another German court this month dismissed Volkswagen’s objections in ruling that local owners of tainted diesel vehicles had a right to return their cars to dealers for a full refund because of Volkswagen’s “massive fraud” with its diesel-powered cars.

South Korea this month banned the sale of 80 Volkswagen models, affecting more than 80,000 vehicles, and around 4,400 Korean consumers are suing Volkswagen and its luxury-car unit Audi (NSU) for damages from its false emissions claims.

Volkswagen has settled emissions claims with regulators and owners of about a half million diesel-powered vehicles. The settlement terms were announced Tuesday by environmental regulators. WSJ’s Lee Hawkins explains. (Originally published June 28, 2016)

Korean authorities also fined Volkswagen and indicted a local executive on charges of fraud linked to the diesel scandal. The auto maker faces additional class-action lawsuits, investigations by prosecutors and punitive damages in Australia, Brazil, Canada, Germany, Ireland, Italy, the Netherlands and Spain.

Johannes Thammer, chief executive of Volkswagen’s Korean unit, recently apologized for misleading Korean authorities, saying: “We will do everything, faithfully, to cooperate with the prosecutor.”

Attorneys outside the U.S. are striving to build on the success of American legal action against Volkswagen. In the June settlement, Volkswagen agreed to pay up to $10 billion to repurchase from consumers affected cars with two-liter diesel engines, including Jettas, Passats, Golfs and Audi A3s. It also agreed to devote another $4.7 billion to environmental remediation and investments in promoting zero-emission vehicles such as electric cars.

European lawyers working with Michael Hausfeld, a leading U.S. class-action lawyer who was part of the plaintiff’s committee that won the U.S. settlement, are assisting Australian and Irish attorneys.

Australia has become a significant battleground because its vehicle-emission regulations are almost identical to European Union laws. If an Australian court determines that Volkswagen’s emissions system contained an illegal element known as a defeat device, Australia could become a precedent for billions of euros in claims in Europe.

In the U.S., Volkswagen admitted to using a defeat device.

Australian Federal Judge Lindsay Foster, who is presiding over a class-action suit in Sydney brought by law firms Maurice Blackburn and Bannister Law, chastised Volkswagen’s lawyers at a hearing on April 29, saying company executives in Germany “obviously think this is some kind of backwater,” according to the court transcript.

He accused Volkswagen of intentionally stalling to delay a ruling in the Australian case until it was able to “bed down” lawyers and regulators in a settlement in the U.S.

“That’s what’s going on, I think, and I’m not having it,” he said, according to the transcript.

‘There is no defeat device. That’s our case.’

An attorney for Volkswagen denied Judge Foster’s charge.

Maurice Blackburn attorney Jason Geisker said the two sides are fighting over “the definition of what is a defeat device” and Volkswagen’s legal team isn’t yielding as it did in the U.S.

“A lot of effort is being put into this case by Volkswagen because of the broader consequences across Europe,” Mr. Geisker said.

In July, Volkswagen’s attorneys in Australia denied the existence of illegal software to manipulate emissions.

“There is no defeat device. That’s our case,” Noel Huntley, an Australian barrister representing Volkswagen, told the court, according to an official transcript of the hearing.

In Europe, Volkswagen has denied that its customers suffered any damages and has ignored or denied claims seeking compensation.

European lawyers allege that Volkswagen is stalling. They note that the one-year statute of limitations for damages suits in many European countries expires on Sept. 18.

“Before that, Volkswagen will do nothing so that as many claims as possible will just go away,” said Eric Breiteneder, an attorney preparing class-action suits in the Netherlands on behalf of 106,000 European car owners and funds with more than €13 billion invested in Volkswagen stocks and bonds.

Volkswagen has declined to enter settlement negotiations with Mr. Breiteneder.

Evan O’Dwyer, an Irish attorney, has filed 20 individual claims against Volkswagen in low-level Irish courts, seeing damages that could go as high as €15,000 a vehicle. Under Irish law, Mr. O’Dwyer is not permitted to comment on the cases to the media.

A&L Goodbody, a law firm representing Volkswagen in Ireland, has threatened to sue Mr. O’Dwyer and his clients for legal fees if he takes the cases to trial. In a letter dated Dec. 16, Goodbody urged Mr. O’Dwyer to drop a lawsuit on behalf of Eithne Higgins, a car owner, saying her complaint was without merit.

—In-Soo Nam in Seoul contributed to this article.

William Boston at [email protected]