"Our national economy benefits from a war that we criticize," she said at the 33rd Kirchentag convention in Dresden. addressing an audience of thousands in a sports arena. "Is it legitimate to earn money from the weapons trade?"
Käßmann cited the Stockholm International Peace Research Institute (SIPRI), which recently reported that Germany's share of the global weapons trade rose to 11 percent between 2005 and 2010, making it the third biggest weapons exporter in the world, behind the US and Russia.
"Our churches cannot stay silent in this situation," said Käßmann.
Käßmann also criticized Germany's mission in Afghanistan and the NATO bombing of Libya.
She said she had been in favour of enforcing a no-fly zone over the latter country, but condemned the "deliberate attempt to kill Qaddafi, with whom we had been doing business with just before."
"That is no path to peace," she said.