Thousands of senior doctors have marched through South Korean capital Seoul to voice support for junior doctors who have been on strike for nearly two weeks over a government plan to sharply increase the number of medical school admissions.

The rally came as the government said it will begin to take steps on Monday to suspend the medical licences of nearly 9,000 medical interns and residents for defying orders to end their walkouts, which have disrupted hospital operations.

Park Sung-min, a senior member of the Korea Medical Association, said in a speech at the rally: “The government’s absurd medical policy has triggered immense resistance by trainee doctors and medical students, and we doctors have become one.

“I’m asking the government: Please, stop the threats and suppression now.”

Protesters chanted slogans, sang and held placards criticising the government’s plan. There were no reports of any violence at the rally.

As of Thursday night, 8,945 of the country’s 13,000 medical interns and residents were confirmed to have left their workplace, according to the health ministry. The government repeatedly said they will face minimum three-month licence suspensions and indictments by prosecutors if they did not return by February 29.

The striking doctors are a fraction of South Korea’s 140,000 medics. But they account for about 30-40% of the total doctors at some major hospitals, where they assist senior doctors during surgeries and other treatments while training.

Their walkouts have subsequently caused numerous cancellations of surgeries and other medical treatments.

Senior doctors have staged a series of rallies backing the young medics but have not joined the walkouts. If they also launch strikes, that would pose a major blow to South Korea’s medical service.

Police said they are investigating five ranking Korea Medical Association officials accused of inciting and abetting the junior doctors’ walkouts. Seoul police chief Cho Ji-ho told reporters on Sunday that officers had raided association offices as part of the investigation.

The government wants to increase South Korea’s medical school enrolment quota by 2,000 starting next year, from the current 3,058, to better deal with the country’s rapidly ageing population. Officials say South Korea’s doctor-to-population ratio is one of the lowest among developed countries.

But many doctors have vehemently contested the plan, saying medical schools cannot handle such a sharp increase in the number of students. They say the recruitment plan also does not address a chronic shortage of doctors in essential but low-paying specialities like paediatrics and emergency departments.

Doctors say adding too many new medics will also result in an increase in public medical expenses since greater competition would lead to excess treatments.

Critics say the doctors simply worry about receiving a lower income due to the rising number of medics.