Tens of thousands of people demonstrated across Finland against racism and violence under the slogan "Enough is enough" following the death of a man who was assaulted during a neo-Nazi rally.

The demonstration snaked through the capital of Helsinki as participants and spectators held green balloons and signs reading "No to Nazism".

A 28-year-old man died six days after hitting his head on the ground after he reportedly spat in front the Finnish Resistance Movement during a rally on 10 September.

Participants and spectators held green balloons and signs reading "No to Nazism" during a demonstration against racism and far right movements in downtown Helsinki, Finland, 24 September, 2016 (Reuters)

A 26-year-old suspect is being held on suspicion of assault and homicide.

Neither the man nor the suspect have been identified by police.

Elsewhere in Helsinki on Saturday, an anti-immigration counter-demonstration took place under the slogan "Close borders!"

No confrontations were reported.