MELBOURNE, Australia — Organizers of the Australian Open faced a rebellion from players after passengers on two charter flights bringing them to Melbourne tested positive for the coronavirus, prompting orders for everyone aboard to go into quarantine for two weeks.

The flights carried 47 players — including several top competitors who had just played the first event of the women’s tour last week in Abu Dhabi, United Arab Emirates — as well as some journalists, coaches and others.

Passengers were asked to have negative test results for the virus within 72 hours of the flights’ departures from Los Angeles and Abu Dhabi. They were tested again after landing in Melbourne, and four people on the flights were found to have the virus as of Sunday afternoon, prompting health officials in the Australian state of Victoria to order that all passengers remain in their hotel rooms for 14 days.

For the players on the flights, that means stricter restrictions than they had planned on before the Australian Open, the first major tennis tournament of 2021, which is scheduled to begin Feb. 8.

Entrants in the tournament agreed to stay in their rooms for 19 hours a day and were allowed five hours daily at the tennis center to practice, train and eat.

Those rules got even tighter Saturday for the 47 players on the two charter flights, who were told they could not leave their hotel rooms at all.

Tennis officials appealed for more leniency for players who repeatedly test negative in their first days in Australia, but government officials declined to soften the rules. Players and tennis officials were not aware when they moved ahead with plans to stage the tournament that the government might impose such restrictions.

“We are communicating with everyone on this flight, and particularly the playing group whose conditions have now changed, to ensure their needs are being catered to as much as possible, and that they are fully appraised of the situation,” said Craig Tiley, the chief executive of Tennis Australia, which is organizing the tournament.

Tiley held a series of difficult videoconferencing sessions with players to explain the changes.

In a livestream on Instagram on Saturday night, Marta Kostyuk of Ukraine told her fellow player Paula Badosa of Spain that she had been blindsided by the ruling and would have to compete on an uneven playing field.

“It’s about the idea of staying in a room for two weeks and being able to compete,” said Kostyuk, who could not remember the last time she did not pick up a racket for two weeks. “We have to stay in quarantine, but we have to fulfill expectations.”

The fast-changing situation and the escalating frustration among the players illustrated just how complicated holding major sports events amid a pandemic can be. Even — or perhaps especially — in Australia, which has had fewer than 30,000 cases since the pandemic began because it imposes some of the strictest rules of any democratic nation, including severe curtailing of domestic travel.

Tennis Australia is spending tens of millions of dollars on special arrangements to meet government health regulations, but the virus has found ways to hobble even the most expensive plans that sports organizations have come up with to remain in operation.

Tennis Australia chartered 17 flights from seven countries to bring players and support personnel to the tournament, limiting capacity to 25 percent on each plane. Tiley said Sunday that players were warned that coming to Australia involved the risk of being considered in close contact with someone who had tested positive, resulting in a mandatory 14-day quarantine.

The flight from Abu Dhabi caused the most consternation because it carried players who had competed in the first event of the year on the women’s tour, among them Veronika Kudermetova of Russia, who played in the final on Wednesday.

Steve Simon, chief executive of the WTA Tour, participated in one of the videoconferences Saturday but the organization, which represents players and tournaments, has so far deferred to Tennis Australia on the consequences of the new cases.

A spokesman for the organization said the WTA is “working with Tennis Australia on the challenges currently being faced with a focus on finding appropriate solutions that support the significant efforts and investment that are being made surrounding the Australian Summer of Tennis.”

The players on the Los Angeles flight included Victoria Azarenka, the 2020 United States Open finalist and a two-time Australian Open champion.

Officials said a flight attendant and two others had tested positive on the Los Angeles flight as of Sunday. Sylvain Bruneau, the coach of the Canadian player Bianca Andreescu, said he had tested positive after arriving on the flight from Abu Dhabi.

“I have followed all of the safety protocols and procedures, including testing negative within 72 hours before the flight departure and felt perfectly fine when I boarded the plane,” Bruneau said in a statement. “I also respected and followed all COVID protocols and guidelines while in the Middle East. I have no idea how I might have contracted this virus. I am extremely saddened and sorry for the consequences now on everyone’s shoulders sharing my flight.”

Another player, Tennys Sandgren of the United States, received special clearance to travel on the Los Angeles flight despite a recent positive test. Health officials determined he was not infectious because he had showed no symptoms and had previously contracted the virus in November. “Some people who have recovered from Covid-19 and who are noninfectious can continue to shed the virus for several months,” the tournament said.

Kirsten Flipkens of Belgium expressed empathy for the players who faced a stricter quarantine because of the new infections. “Everyone should quarantine for two weeks or the Aus Open should be pushed back by a week,” Flipkens wrote on Twitter.

A delay would require a significant reshuffling of a schedule that has already been carefully redesigned, and it would cost Tennis Australia significantly more money to keep more than 1,000 people who have come to Australia for the competition in Melbourne for an additional week. Tiley and his medical adviser said they were waiting to learn more details about the infections.

Ben Rothenberg reported from Washington.