Germany will on Monday announce compulsory testing of ducks and geese for bird flu before slaughtering after two more cases of the H5N8 strain of the disease were discovered, the country's agriculture ministry said.

A new regulation forcing all ducks and geese to be tested for bird flu before slaughter will be announced later on Monday under urgent approval procedures, a ministry spokesperson said. It is set to take force on Tuesday, she said.

This is because ducks and geese show late or even no clinical symptoms of the disease and intensified monitoring is needed, she said.

The move follows the confirmation on Saturday of another case of H5N8 bird flu on a farm in the German state of Lower Saxony, a leading poultry production region.

Another H5N8 case was confirmed in a wild duck in the eastern state of Saxony-Anhalt, bringing to five the number of reported cases in the country since November.

Germany, the Netherlands, Britain and Italy have been since November been hit by the H5N8 bird flu strain which has devastated poultry flocks in Asia, mainly South Korea, earlier this year but has never been detected in humans.

More humane free range poultry farming methods introduced in recent years have increased the risk that farm poultry can contract diseases from wild birds.

The first H5N8 case in Germany was confirmed on Nov. 4 on a poultry farm in Mecklenburg-Vorpommern in east Germany.

Britain on Sunday lifted restrictions around a duck farm in northern England where the disease had been discovered.