Australians have been riveted over the last month by a class-action lawsuit that is pulling back the curtain on strategies that the American drug giant Merck used in its international marketing of the painkiller Vioxx.

Australian newspapers have been covering the court proceedings in daily installments like a soap opera — with headlines like “Drug Representatives for Merck & Co. Given ‘Cheatsheets’ ” and cliffhangers like “the trial continues.”

Merck removed the drug from the global market over safety concerns in 2004. Compared with the $4.85 billion Merck agreed to pay in the United States two years ago to settle with nearly 50,000 people who claimed cardiovascular injuries from Vioxx, legal experts say, the company’s potential liability in Australia is a pittance.

Even the Australian plaintiff’s lawyer in charge of the case against Merck in Melbourne says the best outcome for his side — a favorable decision for several thousand plaintiffs who could potentially join the case — might cost Merck only several hundred million dollars.

That is why, on this side of the Pacific, industry observers are asking themselves why Merck would want to go through another embarrassing airing of dirty linen.

“How much money can Merck be saving on the payouts that would be worth this kind of bad publicity years later?” said Michael A. Santoro, an associate professor at Rutgers Business School who teaches a course on pharmaceutical industry ethics.

But Merck says the issue is not potential liability or negative publicity. The point of trying the case is to stand behind the company’s conviction that it acted responsibly in developing, marketing, and ultimately withdrawing Vioxx, Bruce N. Kuhlik, Merck’s general counsel, said in an interview this week.

With plaintiffs’ lawyers in countries including Canada closely watching the Melbourne trial, Mr. Kuhlik said, Merck was using the same legal strategy it used in the United States: to fight every personal injury case in court and convince judges that patients with idiosyncratic medical histories should not be allowed to sue as a group.

Often, he said, individual plaintiffs cannot prove that they used Vioxx or that the drug caused their health problems.

Merck took Vioxx off the market in more than 80 countries in 2004, after a clinical trial indicated that the drug could raise the risk of strokes and heart attacks. But Merck, in winning most of the cases to reach juries in this country before agreeing to its big settlement, has consistently argued that there is no proof of a causal link between Vioxx and any one patient’s heart problems. The company said at the time of the settlement that judges had encouraged both sides to come to terms.

In the Melbourne trial, which began March 30 and is expected to continue through June, an Australian named Graeme Peterson says that taking Vioxx caused him to have a heart attack in 2003. The plaintiff also accuses Merck of using deceptive and misleading marketing strategies to promote Vioxx.

The judge in the case will determine whether Mr. Peterson’s claims can be applied generally to other members of the class-action group. The defense, which began presenting its case on May 4, plans to introduce evidence showing that Merck extensively studied the safety of Vioxx, that Merck Australia’s marketing was consistent with that study data, and that Mr. Peterson’s heart attack resulted from pre-existing conditions, according to a news release from Merck Australia

But whether or not Merck prevails, the trial has already attracted relentless news and blog coverage of the plaintiffs’ evidence — nearly 600 documents of which were obtained by The New York Times — which detail Merck’s efforts to woo doctors to the side of Vioxx.

Even before introducing Vioxx in Australia in 1999, Merck’s Australian affiliate began to create an arthritis advisory board of influential physicians whose ostensible purpose was to educate the medical community about painkillers.

An internal e-mail message that is included in the plaintiff’s evidence, however, describes the board’s unofficial purpose as priming those chosen doctors to “accept the data and positioning of Vioxx” and “publicly state that Vioxx is superior.”

Other documents indicate the company sought to teach employees to quell doctors’ concerns, as various studies emerged, that Vioxx could increase the risk of strokes and heart attacks. For example, the company started in 2001 to issue a series of training manuals for sales representatives called “Vioxx Objection Handling Module” with talking points to deflect doctors’ questions.

From 2002 to 2005, Merck also sponsored a marketing compilation entitled Australasian Journal of Bone and Joint Medicine, published by Elsevier, a respected academic publishing house. A professor of marketing who testified for the plaintiff said in a written statement that Merck distributed the pro-Vioxx publication to doctors as if it were as an independent medical journal.

Merck said the articles and abstracts had been reprinted from peer-reviewed medical journals.

After Vioxx was taken off the market, some doctors who had supported the drug said they felt disillusioned. The plaintiff’s evidence includes an e-mail message dated Oct. 2, 2004, that Dr. James V. Bertouch, an Australian physician who had been a member of Merck’s arthritis advisory board, sent to fellow board members saying he felt “like the proverbial mushroom” and asked colleagues how they felt being kept in the dark about Vioxx.

Mr. Kuhlik of Merck said that the Australian news media had covered only the plaintiffs’ side of the case and that the totality of the evidence would support Merck’s conduct.

“It is not uncommon that in high-visibility litigation, you find publicity based on facts, documents and testimony that is often taken out of context,” Mr. Kuhlik said. He added that “a short-term negative story” would not deter Merck from what the company considers the correct course of action.

But plaintiffs’ lawyers elsewhere, awaiting their days in court, said they could not explain why Merck would risk such negative publicity in Melbourne after putting Vioxx to rest in the United States

“This fantastic stuff is being revealed to us,” said Michael A. Peerless, a lawyer in Ontario who is representing 1,700 Canadian Vioxx plaintiffs and had just returned from a week observing the proceedings in Melbourne. “Where is it going to get them?”

The trial continues.