Security officials from the federal government and Germany's 16 states will meet next Thursday to discuss plots that may be timed to affect September 27 elections.
The report says the terror attacks may be aimed at forcing a withdrawal of German forces from Afghanistan, where they currently take part in a NATO security and stabilisation mission.
Spiegel says one scenario German officials worry about is a series of simultaneous attacks, either against multiple locations or multiple explosions in the same area.
The BND, a German intelligence service, has also apparently received unconfirmed reports that 15 Islamic terrorists have been trained to demolish buildings at a camp near the border between Afghanistan and Pakistan. Six of the men come from Britain, Germany, France and Italy and the BND is concerned the men may soon return to their home countries.
According to the Spiegel story, the men are thought to have recently left Pakistan.