Police in Germany were accused of excessive use of force by protesters after riot police charged and used batons on a group of anti-fascist demonstrators over the weekend.

The protest alliance Widersetzen, demonstrating against the founding of a youth organization tied to the far-right Alternative for Germany (AfD) party, accused police of brutality against protesters in the western German city of Giessen.

"Police officers cleared a path for the fascists with their batons," spokeswoman Laura Wolf said on Sunday.

Hesse's Interior Minister Roman Poseck meanwhile took the side of the police and said "without the police, there would have been the worst acts of violence and civil war-like conditions in Giessen."

Police said their efforts were aimed at preventing violence between opposing political groups.

Tens of thousands gathered on Saturday, blocking roads into the university town of some 90,000 in an attempt to disrupt the formation of the far-right youth wing.

Police in Germany have been accused of using excessive force at pro-Palestinian, environmentalist and anti-fascist demonstrations, where protesters have been injured by chokeholds, punches to the head and being thrown to the ground.

The alliance said it initially had no figures on injured demonstrators or on people taken into custody. A local hospital told dpa several people had reported with injuries to hands and legs. Police said around 10 to 15 officers also suffered minor injuries.

Marburg lawyer Jannik Rienhoff, who represents several activists taken into custody, said the basic right to freedom of assembly had "not been taken particularly seriously" even beforehand.

Suraj Mailitafi of Widersetzen said the city of Giessen and police created a climate of fear before the protests and that participants were the victims of "arbitrary violence," while the far-right was courted.