South Korea's health authorities Tuesday reported two more deaths from the H1N1 virus infection, bringing the nation's flu death toll to 20.

A two-year-old girl and a 66-year-old man have died after being infected with the type-A influenza, according to the Ministry for Health, Welfare and Family Affairs.

Both were categorized as "highly vulnerable" patients to the contagious virus due to their chronic diseases. The baby had suffered cyanosis while the man had been treated for kidney cancer, according to Yonhap News Agency.

Since the swine flu pandemic was first reported in South Korea in May, the H1N1 virus has claimed the lives of 20 South Koreans. Most of them were categorized as highly vulnerable patients who were either elderly or suffering from chronic diseases.

The government is scurrying to stockpile antiviral drugs and vaccines for fear the flu may spread more widely in the autumn, with a plan to vaccinate 27 percent of its 49 million people by February next year.