Thousands of South Korean doctors held a mass rally on Sunday against government plans to increase medical school admissions, defying official calls for trainee physicians who had also walked off the job in protest to return to work.

Up to 40,000 doctors joined the rally, demanding the government scrap the plan, according to the Korean Medical Association (KMA), which represents private practitioners and had organised the protest.

Police put the number of demonstrators at about 12,000.

The rally comes a day after a government deadline for the trainee doctors to return to work expired. Nearly 9,000 resident and intern doctors at major hospitals, or about 70 per cent of the country’s total, walked off the job in late February, leading to the cancellation of some surgeries and treatments and straining emergency departments.

Joo Soo-ho, an official at the KMA, said the government should reform the existing medical system first before raising medical school quotas. The government wants to boost medical school admissions by 2,000 starting in 2025 from the current annual figure of 3,000, and eventually add 10,000 more by 2035.

“It was the government that set the deadline, and regardless of the deadline and pressure, we will continue to push forward as we think,” Joo said.