Based on results from 49% of polling stations, Prime Minister Robert Fico's leftist Smer party has 36.7% of votes.

Although the conservative SDKU has polled only 14.95% so far, its five-party coalition is on track to win 76 of the 150 parliamentary seats.

Growing public debt and a political fund-raising scandal may have dented Smer's popularity, analysts say.

Slovakia's worsening ties with Hungary also dominated the election campaign.