A human H5N6 avian flu case has been reported in Shenzhen City in south China's Guangdong Province.

The patient, a 26-year-old woman, is in critical condition and is receiving treatment in a local hospital, the Guangdong health department said on Tuesday.

Experts believe the infection is an isolated case, and there is little possibility for the virus to spread for the time being.

The world's first human H5N6 infection was reported in May 2014 in southwest China's Sichuan Province. Four cases have been reported so far around the world, and were all confirmed to be isolated cases.