Lawyer Natasa Pirc Musar won the second round of Slovenia's presidential election on Sunday and will become its first female head of state, preliminary results showed.

Pirc Musar, 54, won around 54 percent of votes in the runoff, while her rival, right-wing politician and former Foreign Minister Andze Logar, won just over 46 percent, according to election commission data based on 99 percent of the votes counted.

Turnout was 49.9 percent, the commission data showed.

Pirc Musar will take office on December 23 when the second mandate of the incumbent President Borut Pahor expires.

"I will do my best to be a true president for all, to work for fundamental and constitutional human and democratic rights and democracy," Pirc Musar told reporters after claiming victory.

Although the role is mostly ceremonial, the president is commander in chief of the armed forces and also nominates several top officials, including the central bank governor. Most of the nominations have to be confirmed by parliament.

Pirc Musar, a former TV presenter who became an influential lawyer, campaigned on issues including the rule of law and social welfare. 

Her rival Logar, 46, is a member of the right-wing Slovenian Democratic Party of former Prime Minister Janez Jansa, who lost April's parliamentary election to the environmentalist Freedom Movement of Robert Golub.

Commenting on the outcome of Sunday's presidential election, Golub told reporters, "I am confident that we will work well together to address the common challenges of the future."

(With input from Reuters)