Swedish Centre Party leader Annie Loof criticized Liberal leader Johan Perhson for his party's willingness to work with the far-right Sweden Democrats in a debate Saturday.
The two leaders met for the final debate one day ahead of parliamentary elections.
"You are collaborating with Nazis," Loof said in the debate that was dominated by discussions about the far-right Sweden Democrats Party.
Pehrson retorted that it is possible to talk to all parties.
But Loof took offense and said: "This is where we differ, that it is fascinating how he as a liberal politician defends SD (Sweden Democrats)."
She said, "Good luck with your cooperation with the Sweden Democrats, Johan Pehrson."
Pehrson has been criticized by other parties, including a member of the Left Party, Linda Snecker, who accused the Liberal Party on Thursday of wanting to forcibly take pre-school children into custody who do not speak perfect Swedish.
Pehrson responded to Snecker's statements on Twitter by saying it is a "serious" issue and the Liberals have proposed a mandatory language test for two-year-olds who are not enrolled in preschool.
But Snecker said it is a policy that constantly "paints certain groups of people as a problem, instead of trying to solve social problems. I think that's important to point out."
The populist Sweden Democrats are set to become the second largest party in parliament, the Riksdag, after polls are tallied Sunday.
