The statement from the Chancellor's office follow a similar declaration by Foreign Minister Frank-Walter Steinmeier on Thursday.
"We are neither being asked to do that, nor will we do it," Steinmeier told journalists in Berlin after meeting with his British counterpart Philip Hammond.
Military action had to be embedded in a "political strategy" to counter Isis, Steinmeier said.
Germany's pledge to deliver weapons to Kurdish forces in northern Iraq was "not small," he added. "That's the right amount of responsibility for us to bear."
Hammond also ruled out British strikes on Isis positions inside Syria.
The former Social Democrat (SPD) candidate for Chancellor made his comments after the foreign affairs spokesman from Chancellor Angela Merkel's CDU party had suggested Germany would be involved in the strikes.
“I won't rule out [German participation] in these air strikes,” Philipp Mißfelder, foreign affairs spokesman in the Bundestag for the CDU had said.
The fight against Isis is “something that binds us all together” which “we will be dealing with for a long time,” Mißfelder told broadcaster ARD. “I believe strongly that we must support the Americans.”
Germany might also send units to take part in aerial surveillance and allow flights over its territory to and from the conflict zone, Mißfelder said, but added that deployment of ground troops “from the West as a whole” was out of the question.
That didn't rule out sending German soldiers on training missions, Mißfelder said.
He went on to reiterate his statement in a tweet, saying “We should support the USA with air strikes against Isis in Syria with our capabilities!”
The German airforce is already deployed to Estonia, where four Eurofighters guarded by 160 soldiers have been flying patrols since September to discourage Russian aggression against the Baltic states.
Germany has a handful of soldiers in northern Iraq who were sent to the Kurdish capital of Irbil to help organize German aid for the Kurds who have been fighting Isis.
France, meanwhile, pledged on Thursday to join air strikes against Isis "if necessary".
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