A Moroccan asylum seeker has been given a life sentence after being convicted of two terror-related murders and eight attempted murders for a stabbing attack in Finland last year.

Abderrahman Bouanane, an alleged sympathiser of Islamic State, was found guilty of the August 18 stabbing rampage in the south-western city of Turku in the first terror trial in the Nordic country.

Bouanane, who is in his early twenties, had pleaded guilty at the southern Finland district court but denied committing a terrorist act as prosecutors had alleged.

They said he was motivated largely by hatred after heavy bombardments by the Western alliance in the Syrian city of Raqqa.

A life sentence in Finland is on average between 12 and 20 years, with most serving 14 to 16 years.

Prosecutor Hannu Koistinen said Bouanane wanted to spread fear among citizens and probably wished to be shot by police and die as a martyr.

He told investigators that his initial plan was to decapitate his victims.

Bouanane was stopped by police, who shot him in the thigh after the stabbing rampage in Turku's main market square.

Defence lawyer Kaarle Gummerus said Bouanane, who arrived in Finland in 2016, had only become radicalised shortly before the attack, so it could not be described as a planned terror offence.

Investigators said the fact that his asylum application was rejected was probably not a motive for the attack.