Speaker of Parliament Anu Vehviläinen (Cen) has condemned a "threatening" tweet sent by MP Ano Turtiainen and said she intends to bring the matter before Parliament when MPs return from the Easter holiday.
In his tweet, Turtiainen said that his friend is ready to kill if the wearing of masks becomes mandatory in Finland.
"My friend said 'I am willing to kill if someone in this country is forced to put on a mask'," Turtiainen wrote. "Well, I wouldn't just watch that from the sidelines either. Greetings to colleagues who are in favour of a mask mandate."
In her own tweet, Vehviläinen wrote that threats of violence are always to be condemned.
"MP Ano Turtiainen's threatening tweet will come before Parliament immediately after Easter," Vehviläinen added.
Among other MPs, Mikko Kärnä (Cen) and Hussein al-Taee (SDP) also condemned Turtiainen's tweet, while Finns Party MPs Sanna Antikainen and Veikko Vallin supported Vehviläinen's comments.
Vehviläinen has previously remarked on Turtinen's conduct in relation to the issue of wearing masks after Turtiainen clashed with Deputy Speaker of Parliament Juho Eerola (Finns) earlier this year.
On that occasion, Turtiainen had refused to comply with the Parliament's recommendation on the use of face masks, citing health reasons, which led to a verbal disagreement with Eerola.
Turtiainen has formed his own one-man parliamentary party since being expelled from the Finns Party's parliamentary group last year. He was subsequently removed from the party in February.