Hackers have been trying to replicate Stuxnet, a computer virus tailor-made to knock out Iranian uranium-processing machines, according to a German government minister, DPA reported.
Speaking on a late-night show on NDR television Tuesday, Interior Minister Thomas de Maiziere said his office had already observed the "first copies" of the virus.
His ministry oversees government computer security.
German hacking enthusiasts drew world attention last year to Stuxnet, a sabotage program targeting industrial plants managed by Siemens software.
Last week, the New York Times reported that Stuxnet had been fine- tuned in an Israeli nuclear plant before it was unleashed against Iran's centrifuge plants, adding to suspicions that western intelligence services may have devised the virus as a cyber-warfare weapon.