"Bird flu has been identified at an egg farm in Barneveld with around 30,000 chickens," the Dutch government economics ministry said in a statement today.

"It is highly likely that it is the mild H7 strain," it said, adding that tests were expected to confirm the strain on Friday.

As the H7 form can mutate into a highly pathogenic strain, all 30,000 birds will be culled, the ministry said.

A three-week ban on transporting poultry has been implemented within a one-kilometre (just over half a mile) radius around the farm, where 17 other poultry farms are being tested.