SEOUL - Three days into a mass walkout by trainee doctors, patients in South Korea expressed growing worry and frustration on Thursday as hospitals nationwide delayed surgeries and emergency rooms turned away patients.

With more than 8,400 doctors staying off the job in a protest over government plans to step up medical school admissions and no immediate sign of resolution, some of the sick and hurt voiced concerns about getting treatment.

"If the government truly cares for its people, I hope they take a step back now, and doctors also take a step back, so that patients won't be hurt," said a 34-year-old office worker with a broken leg that required surgery.

The man, who asked to be identified only by his surname, Kim, said he had been turned away from three hospitals before finally receiving treatment at the state-run National Medical Centre in the capital, Seoul.

"I'd been in an accident before and at that time, my abdomen was cut open. If that had happened while doctors were on walkout like now, I would have died," he added.

Emergency departments at all but one of South Korea's biggest hospitals were on red alert as trainee doctors protested the plan to remedy a shortage of as many as 15,000 doctors expected by 2035, amid one of the fastest-ageing populations in the world.

Asthma sufferer Lee Joo-hyung said he had been lucky to get treatment, but worried about getting to see a doctor at his next appointment three months from now.

"Since many doctors have submitted their resignations, we don't know what will happen," the 31-year-old teacher added. "So I'm really worried about that."

Nearly two-thirds of the country's trainee doctors have walked off the job since Tuesday after submitting resignations, defying government orders to return to work or face punishment and even arrest.

They say the real issue is pay and working conditions, not the number of doctors. Some say more admissions will compromise the quality of education, a worry also for senior doctors.

A recent Gallup Korea poll showed about 76 percent of Koreans favour the government's plan, however, regardless of political affiliation.

Nevertheless, as the disruption grows, the government told patients to go to smaller clinics, while advising the seriously ill or those needing urgent care to turn to state-run and military hospitals.

"Doctors are supposed to treat patients, so it seems unreasonable for them to go on strike," said Kim, who was treated for his broken left leg. REUTERS