An additional 40 cases of influenza A were confirmed Tuesday, bringing the nation's total number of infections to 535, the nation's health agency said.

The patients, including 24 Indonesians, tested positive for the H1N1 virus after showing flu-like symptoms upon their recent arrival here, according to the Ministry for Health, Welfare and Family Affairs.

The Indonesians came here last week to participate in a world choir competition in the country's southeast. Five South Korean nationals were infected via contact with the choir members.

Concerns are growing that the disease might be spreading more quickly than anticipated earlier, with the number of cases rising at a faster clip.

The government has set aside 175 billion won ($134 million) to secure enough vaccines to inoculate around 13 million people against the new flu strain. The vaccination will be available beginning in November, ahead of the winter flu season.

Of the total flu cases, 410 were inbound travelers. As of Tuesday morning, 173 people remained in isolation for treatment ― with the remainder having been sent home after showing no further symptoms.

chojh@koreatimes.co.kr