Germany and Austria share hundreds of kilometres of frontier, including along the state of German Bavaria, where the attack occurred.

“Police have significantly increased security measures so they are poised and fully ready to act,” public security chief Konrad Kogler told state broadcaster ORF, without elaborating.

He added that 42 elite so-called “Cobra” officers have been dispatched to Munich to assist police in their hunt for gunmen who killed at least eight people in a shooting rampage at a shopping centre in Munich.

“The entire Cobra team has been placed on high alert so that they are ready to jump into action,” Kogler said.

He added there were “no concrete indications” of an imminent threat in Austria and the current terror threat level has not been increased.

The country has been on raised alert since last January's deadly attack on the Charlie Hebdo satirical weekly offices in Paris.

Austrian Chancellor Christian Kern expressed shock over what he called “harrowing, dramatic hours” after the Munich shootings.

“My biggest respect goes to the police and rescue workers, who are working to protect people in Munich,” he said in a Facebook post.

Meanwhile, Interior Minister Wolfgang Sobotka cut short his holiday to return to Vienna after news of the attack in Bavaria broke.

“Austria has taken all the measures necessary in the situation. But it's very difficult to protect yourself against these kinds of terrorists or criminals,” Sobotka said. “This could also happen here.”