Police Commissioner Seppo Kolehmainen has called for the end to the use of violence by organisations.
He said however that outright banning groups would be problematic because even if they were officially disbanded, members could continue their activities independently.
"It is the violent behaviour that must be stopped," Kolehmainen said. "Violent threats are included in this. It is vital that illegal activities are addressed."
Kolehmainen's comments on Sunday came as his department continues to investigate the death of a 28-year-old man.
Railway station aggravated homicide investigation
On Sunday afternoon (September 18) Helsinki Police said that they had detained a man born in 1990 in connection with the case.
The suspect is allegedly a member of the right wing extremist group the Finnish Resistance Movement and is suspected of assault and aggravated homicide, according to police.
The father of the victim has been very vocal about his son's death, and claims that his son died from complications of injuries he suffered during the confrontation outside Helsinki Central Railway Station, where members of the FRM were demonstrating on September 10.
The preliminary investigation continues, police said.
UPDATE September 18, 2016, 6:14 pm: Changes to this story were made to reflect that the suspect police detained is a member of the FRM.