Finland's Prosecutor General Raija Toiviainen wants to bring charges against Finns Party MP Juha Mäenpää for inciting hatred against an ethnic group.
As Mäenpää delivered a speech before the legislature last June, he likened asylum seekers to an invasive species.
According to news service STT, Mäenpää said he was not guilty of the offence, saying that his statement was part of a spontaneous debate, and not criminal speech.
A preliminary police investigation into the matter found grounds for the charge. However, to move forward with an indictment, the prosecutor needs to secure the approval of five-sixths of parliament.
That is, a total of 167 out of parliament's 200 members would need to vote to consent to the prosecutor's proposal.
The opposition Finns Party currently has 39 MPs in parliament, and if they all vote to reject the proposal, the charge cannot be brought forward.
Finns Party chair Jussi Halla-aho told Yle that his party plans to oppose the proposal. Halla-aho was convicted of inciting hatred against an ethnic group in 2012.
Parliament is expected to look into the matter as soon as its spring session starts in early February.