North Korea has issued an emergency warning against bird flu in its provinces of South and North Pyongan and North Hamgyong.

North Korean authorities are focusing quarantine efforts on the provinces after cases of bird flu were reported in March in two to three chicken factories, including one in Pyongyang.

The virus is also rapidly spreading in China's Liaoning Province that borders the North.

Migratory birds flying from the northern hemisphere to Australia in winter travel through three Chinese provinces bordering North Pyongan and North Hamgyong, raising the possibility of a further spread of the virus.

The North's quarantine authorities from its central government and provinces have taken swift action, including the setup of an emergency communications system for bird flu data.