A mild form of the avian virus bird flu has been found on a chicken farm in Zeewolde in Flevoland province, the economic affairs ministry said on Tuesday.

The 24,000 hens on the farm are being destroyed and a one-kilometre ban on poultry transports has been imposed.

Last week, a mild form of bird flu was found on a chicken farm in Lochem in Gelderland.

Although the bird flu variety is mild, it can mutate into a highly contagious and for chickens deadly form. The birds are therefore always destroyed and an isolation cordon set up.

The last outbreak of bird flu was in spring 2011.