AMSTERDAM, April 13 (Reuters) - The Dutch Agriculture Ministry will lift an order on April 15 to keep commercial poultry indoors, which was introduced to prevent a possible bird flu spread, the ministry said on Friday.

The measure was put in place in early March to prevent contact between poultry and wild birds in the Netherlands -- Europe"e;s second-biggest poultry producer after France -- during the migration season in the spring.

"Poultry can be allowed outdoors because the monitoring of wild birds in the Netherlands and the European Union showed no traces of the diease," the ministry said in a statement.

Veterinary experts believe that migratory birds represent a serious risk in the spread of the deadly H5N1 avian flu virus.

The virus originated in Asia and is known to have infected nearly 300 people in 12 countries since 2003, killing more than half of them.

The Netherlands, a top world poultry exporter, has never reported H5N1 in commercial poultry but it was hit by H7N7 avian flu in 2003, which led to the culling of 30 million birds, about a third of the poultry flock, as well as one human death.