With 35 percent of ballots counted, the Social Democrats are ahead with 18.9 percent of votes, trailed by the center-right National Coalition Party with 17.2 percent.
The liberal Center has 15.4 percent, while the right-wing Finns party is fourth with 15.1 percent. Voters are choosing among 2,468 candidates from 19 parties to fill the legislature's 200 seats.