The Health Ministry extended a back-to-work order for doctors to the entire country and filed a complaint with police against at least 10 doctors it said have not abided by an order that has been in place in Seoul since Wednesday.
But the Korea Medical Association said on Friday it plans to organize a nationwide strike starting Sept. 7, for an indefinite period, unless the government drops its reforms.
The escalation in the dispute comes as South Korean officials tackle a fresh wave of COVID-19 infections. Onsite night-time dining at food outlets in the capital and Seoul metropolitan area was restricted for the first time since the beginning of the outbreak.
After aggressive tracing and testing contained a large outbreak earlier this year, the country suffered a setback this month when a church cluster spread to a political rally.
Officials reported 371 new infections as of midnight Thursday, bringing the total to 19,077, including 316 deaths.
"To protect lives and safety of the citizens in a grave crisis of nationwide coronavirus transmission, the government inevitably expanded the back-to-work order for trainee and professional doctors today nationwide," Health Minister Park Neung-hoo said.
At the heart of the dispute are government plans to boost the number of medical students over several years, establish public medical schools, allow government insurance to cover more oriental medicine, and introduce more telemedicine options.
Almost 16,000 intern and resident doctors have been on strike since Aug. 21 over the government's plans, which it said were necessary to better prepare for public health crises.