The German police have warned of a planned terror attack in the southern city of Munich on the New Year's Eve, calling on the public to avoid large gatherings and two key train stations.

"Current indications show that a terror attack is being planned in Munich,” the police wrote on Twitter on Thursday, saying the threat of the potential attack was "serious” and “imminent.”

“Please avoid gatherings of people and the Munich and Pasing train stations," the tweet added, referring respectively to the city’s main train station and another key public transportation hub.

The stations have suspended train services and been evacuated.

On Facebook, the city’s police wrote that according to "serious information, there will be an attack tonight," describing the nature of the information as a tip it had received.

A police spokeswoman told AFP that they had "reliable information" that a group was planning to act as festivities were well underway. Although the stations have been evacuated, the spokeswoman said the attackers could seek another target.

Security measures have also been ratcheted up at the Brandenburg Gate in Berlin, which is currently hosting thousands, who have gathered for the New Year celebrations, with the police having banned large bags and backpacks from the site.

Elsewhere across Europe, Paris and Brussels have banned pyrotechnics.

Authorities have also put other sorts of New Year festivities on hold in the Belgian capital, citing fears of attacks by Takfiri terrorists.

On November 13, Paris was rocked by deadly terror attacks claimed by the Daesh Takfiri group. France says the strikes, which claimed 130 lives and left hundreds more injured, had been planned in Belgium.