A group of Berlin police officers helping with security ahead of next week's Group of 20 (G20) summit in Hamburg has been sent home after some reportedly partied excessively at the barracks where they were staying.

More than 220 officers were sent back to the German capital after what Hamburg police called "inappropriate and unacceptable behavior" by a minority of the group.

Berlin's BZ newspaper reported that the antics allegedly included police officers urinating on a fence and an officer dressed in a bathrobe dancing on a table with a weapon in her hand.

Berlin police spokesman Thomas Neuendorf described the behaviour Tuesday (27 June) as "simply embarrassing".

The officers were housed at barracks north of Hamburg. They were scheduled to be relieved by others from Berlin before the July 7-8 summit.

The G20 summit has already come under some security concerns, with a left-wing anarchist group called Shutdown G20 claiming responsibility for a series of arson attacks on local railways.