German police have urged residents of Berlin's southern suburbs to stay indoors as they scoured the area for a wild animal on the loose, apparently a lioness.

Police first issued the alarm in the early morning hours on Thursday, after two people saw what appeared to be a lioness chasing a wild boar down a street less than five kilometres from the German capital.

"Around midnight, we received a message hard to imagine. Two passersby who saw one animal chasing another," Daniel Keip, Brandenburg police spokesman, told RBB radio.

"One was a wild boar and the other apparently a wild animal, a lioness. The two men recorded a video on their phones and even experienced policemen had to concede that it was probably a lioness," he said.

As authorities, backed by several helicopters, scoured the area around the communities of Kleinmachnow, Teltow and Stahnsdorf at the start of the workday, according to local media, police urged residents to stay indoors.

'Stand still'

"The wild animal that escaped has not yet been found!" the police of Brandenburg, the region around Berlin, wrote on Twitter around 7:30 am. "We ask you not to leave your houses."

It remains unclear where the feline could have come from.

"No animal parks, zoos or circuses are missing an animal of this kind," the police spokesman told RBB.

A spokeswoman for the Kleinmachnow municipality told RBB that daycare centres had been told to keep children inside, and vendors at a local market were asked not to set up their stalls.

Should anyone run into the wild animal, the main thing is not to panic, said Florian Eiserlo of the "Vier Pfoten" (Four Paws) animal welfare organisation.

"Stand still, stay calm, try to head to a safe are a such as a car or a building," Eiserlo told the Rheinische Post newspaper.