Finns Party leader Riikka Purra says that her party cannot sign off on a government programme that does not include significant tightening of immigration policy.
She told Yle that certain issues needed to be addressed if she were to join a coalition with the National Coalition Party's Petteri Orpo, who is leading government formation efforts after his party won the most seats in Sunday's elections.
Purra said that her party also regarded climate and energy policy as red lines. She has said Finland needs to abandon the target of becoming carbon neutral by 2035, pushing the date back to 2050.
The NCP, meanwhile, said in the election campaign that it would stick to the 2035 deadline.
Immigration, though, is likely to be the biggest sticking point as the Finns discuss any government programme.
"Immigration into low-paid sectors has to be more tightly controlled," said Purra. "The Finns Party believes it is fine to come to the country to live and work, so long as you make ends meet with your own pay."
The NCP's programme included the goal of increasing work-based immigration to boost the economy as the population ages. The Swedish People's Party, which would be needed as part of any Finns Party-NCP coalition, is also a strong promoter of immigration.
Purra acknowledged their differences and said she did expect compromises.
"We have a broad immigration policy programme," said Purra. "I don't believe, though, that we would get all of it through."
In other post-election news, the Social Democrats re-elected Antti Lindtman as the leader of their parliamentary group, and Finns Party MPs voted in Lulu Ranne as the chair of their group.