Truck ploughs into Christmas market full of people in Berlin.

At least nine people have been left dead and 50 people injured after a truck ploughed into a Christmas market in Germany on Monday evening local time, police say.

German police say a man suspected to be the driver of the black Scania truck with Polish licence plates has been arrested near the scene. It is also being reported that a passenger in the truck has died at the scene.

It is not yet known why the truck veered away from the road and into the Breitscheidplatz market near the Kurfuerstendamm and the Kaiser Wilhelm Memorial Church, a popular shopping area in west Berlin. One eye-witness reported seeing the semi-trailer travelling at approximately 60km/ph as it drove into the popular market.

Local media said the first indications pointed to an attack but are yet to speak about motivations or release any further information.

Police cars and ambulances have converged on the scene and people are being treated on the ground.

Many are comparing the horrific scenes to that of the Nice terror attack, with one tourist from England telling the Associated Press "It was definitely deliberate."

Australian tourist Trisha O'Neill was at the markets at the time of the attack and said, "I could hear screaming and then we all froze. Then suddenly people started to move and lift all the wreckage off people, trying to help whoever was there.

"Eventually we had to and there was blood and bodies everywhere," she said.

"People, including children and older people, weren't moving — people were crying and I just burst into tears."

The popular market was filled with a number of stalls selling handmade jewellery, crafts, sweets, mulled wine and other Christmas treats. There was also a mini-ferris wheel and carousels for children.

Chancellor Angela Merkel is being briefed on the situation but is yet to address the public.