Thousands of trainee doctors submitted their letters of collective resignation in protest against the government's plan to boost the number of medical students on Tuesday, aggravating fears of a major void in public health.

As of Monday at 11 p.m., 6,415 trainee doctors at 100 teaching hospitals had handed in their resignation letters, with about 1,630 of them walking out of the hospital, according to the Health Ministry on Tuesday. The rate of junior doctors resigning is over 55 percent, as South Korea has some 13,000 trainee doctors across the nation. The government immediately ordered 728 of them to return to work, in addition to issuing the same order to 103 doctors previously.

The Health Ministry is planning to inspect 50 more hospitals at the site and monitor trainee doctors who are absent for a long period. If they do not return to work despite the order, their licenses could be suspended.

Following an amendment to the Medical Act that came into effect immediately after its promulgation on May 19 last year, doctors' licenses can be revoked if patients are fatally harmed, or they may face confinement if involved in illegal strikes or the disruption of work, or if they violate the law on gatherings and demonstrations.

With trainee doctors stopping work at some hospitals, some patients have already experienced delays in surgeries and other treatments. No major disruptions had been reported as of Tuesday afternoon. As of midnight on Monday, 34 cases of damage had been reported to the support center for physicians' collective action. Twenty-seven cases were related to surgery cancelation and delayed hospitalization, while the rest were related to medical appointment cancelations and incidences of medical refusal.

"We are deeply disappointed and concerned that the collective action by trainee doctors has led to a disruption in medical services, such as the cancellation of surgeries," Park said.

Meanwhile, hospitals worry about how long they can maintain their services with the continuing walkouts. The current emergency medical care system is believed to be sustainable for about "two to three weeks" due to the collective resignations of doctors, according to medical experts and the Health Ministry.

The burden is especially heavy on advanced general hospitals, which have a high proportion of medical residents.

Based on the experience of an indefinite general strike of trainee doctors when the Ministry of Health and Welfare pushed the expansion of medical schools in 2020, it is expected that a 30 to 50 percent reduction in treatment will be inevitable.

"The government will put in utmost efforts to operate an emergency medical system to minimize possible damage to the patients."

The ministry is focusing on preventing the overload of the health care system by first shifting the focus of upper-level general hospitals to severe and emergency patients, and allowing mild and nonemergency patients to go to general hospitals.

To cope with a potential disruption of medical services, the government will also extend operating hours at 97 public hospitals and emergency rooms at 12 military hospitals will open to the public, Park said.

Meanwhile, medical students are also participating in the strike against the government with a collective leave of absence. As of Monday, 1,133 students have submitted for a leave of absence from seven medical universities, according to the Education Ministry.

"The government is over-producing doctors by increasing the quota to 5,000 from the current 3,000. The Health Ministry, which is responsible for taking care of future generations and the health of the people, is not thinking about the confusion and damage people will face due to having incompetent doctors," the Korean Medical Association said in a statement released Tuesday.

The submissions were accepted for just four students, who had claimed they had to serve their military duty or had personal reasons. The Education Ministry has yet to figure out whether the remaining 1,129 students are all participating in the collective action.

How many more students will take collective action remains uncertain. Currently, some 18,800 are registered as medical students in the country, the ministry said.

The ministry said it is closely monitoring the moves on campus while urging schools to thoroughly guide students and manage academic affairs by complying with relevant laws and regulations.