Voters in Slovakia are selecting a new head of state in a runoff that could give the country its first female president.

Zuzana Caputova, an environmental activist, is up against European Commission vice-president Maros Sefcovic in the vote for the largely ceremonial post in the nation of 5.4 million.

Caputova won the first round two week ago with 40.6 percent of the vote while Sefcovic was a distant second with 18.7 percent.

Caputova attracts voters appalled by corruption and mainstream politics. Sefcovic is a career diplomat who is supported by the leftist Smer-Social Democracy party, a major force in Slovak politics.

The winner will become the country's fifth head of state since Slovakia gained independence in 1993 after Czechoslovakia split in two.

Incumbent Andrej Kiska did not stand for a second term.