SEOUL (REUTERS) - South Korea's agriculture ministry raised the country's bird flu alert status to the highest level for the first time on Thursday (Dec 15) as the disease has spread quickly nationwide.

The heightened alarm status comes as the country grapples with an outbreak of the highly pathogenic H5N6 bird flu that started a month ago. Since then, South Korea, Asia's fourth-largest economy, has culled over 12 per cent of its poultry population to contain the spread of the virus.

The Ministry of Agriculture, Food and Rural Affairs said in a statement released on Thursday that it will come up with detailed measures to combat the disease under the higher alert status after consulting with related ministries.

The ministry had already ramped up quarantine measures to tackle the spread of the H5N6 virus including issuing a temporary nationwide movement ban as an increasing number of farms have reported outbreaks.

There have been 53 cases of the virus confirmed since mid-November, with another 21 cases being tested, according to the ministry statement.

Outbreaks of avian influenza have been reported in Japan and several European countries including France, which raised its bird flu risk level to high last week.

Cases of human infections from the H5N6 virus have been previously reported elsewhere including China, where it killed 10 people, but no cases of human infections have been detected in South Korea.