Of all the parties in parliament, the Left Alliance is most strongly in favour of a referendum on Nato membership, according to a poll by Finnish news agency STT.
The agency surveyed the leaders of nine political parties via email regarding their stance on Finnish Nato accession.
In the wake of Russia's attack on Ukraine, public opinion seems to have swung behind the notion seeking membership in the military alliance, with a recent Yle poll recording 53 percent support for Nato membership.
Nato rules require countries seeking membership to demonstrate their bid is supported by the people.
The Left Alliance said that any bid to join the alliance should be preceded by a referendum supported by a majority of the people.
The Social Democrat's leader, Antti Lindtman, said any "security solutions should be anchored in the people's broad support."
The Centre Party said membership in the organisation would require the support of a "significant majority."
Earlier this week an American foreign policy argued that Finns had "misunderstood" the purpose of Nato.
STT conducted its poll between Thursday and Friday this week.