German authorities said a case of H5N1 bird flu had been discovered during initial tests on a poultry farm in the eastern state of Brandenburg.
The case was discovered in a duck farm, which was carrying out its own tests, the Brandenburg state agriculture ministry said on Friday.
The H5N1 virus mainly affects birds but occasionally jumps to people. Experts fear it may mutate into a form that could spread easily among humans, who have no natural immunity against it.
The initial finding was confirmed by a state laboratory, and final tests are currently being carried out, the state ministry said.
The farm has been sealed off and its poultry will be culled, the statement said.
The cause is unknown and an investigation has started.
Bird flu is currently present in Asian countries including China, Cambodia and Indonesia. It has also been reported in wild birds in parts of Europe.
On January 29, the United Nations' Food and Agriculture Organization (FAO) said governments must not allow financial constraints caused by the current global economic crisis to stop them from keeping their guard up against the spread of bird flu.