In total, 34 people involved in blocking a motorway to prevent anti-Zwarte Piet demonstrators reaching the Frisian town of Dokkum face will face legal action, the public prosecution department said on Thursday.

The Piet supporters put road safety at risk by blocking off the motorway with cars and other vehicles, the department said.

Several dozen people, many thought to be members of extreme right nationalist organisations, stopped the buses carrying some 120 demonstrators by braking in front of them on the highway, forcing all traffic to a halt.

The action led to the demonstration being cancelled by the mayor on public order grounds even though the demonstrators had been given a licence to protest during the arrival of Sinterklaas.

No-one was arrested during the stand-off but police did photograph the number plates of all vehicles involved in forming the blockade.

The public prosecutor also said that the 34 people who face court broke the law by preventing a demonstration taking place.

The hearings will held over three days – June 6, 7 and 8 – at Leeuwarden district court.