Germany must stop using its past as a "shield" and use its armed forces more frequently and decisively, federal president Joachim Gauck has warned, in the clearest sign yet that country's longstanding aversion to the use of its military may be beginning to crack. "Germany can't carry on as before," Mr Gauck said on Friday, pulling few punches in a speech that cited German indifference and European navel-gazing amid "rapid" and "dramatic" new threats to the "open world order". "When the last resort – sending in the Bundeswehr – comes to be discussed, Germany should not say no on principle," the president said. Mr Gauck appeared as the keynote-speaker at the Munich Security Conference – the world's largest annual gathering of defense chiefs and politicians. (Read more: Japan to bolster military, boost Asia ties to counter China)

German Chancellor Angela Merkel, walks past flags of the European Union and Germany. Sean Gallup | Getty Images

In a 30-minute oration pitched as much to Germany's domestic audience as to delegates in the cordoned-off precincts of the Bayerischer Hof hotel, Mr Gauck called for Germany to "do more to guarantee the security that others have provided it with for decades". Military engagement remains a particularly sensitive political and social issue in Germany decades after the second world war. A YouGov survey of over 1,000 Germans, conducted earlier this week and published on Friday, found that 45 percent believe the Bundeswehr is already doing "too much" overseas, while 30 percent believe the current level of intervention is appropriate. The country's political establishment remains divided too. Both foreign minister Frank-Walter Steinmeier and Chancellor Angela Merkel remain cautious about expanding German military ambitions. (Read more: Roubini doom scenario: It looks like 1914 again)