Almost 1.7 million Slovenians are eligible to cast ballots at polling stations across the Alpine country on Sunday, with the election commission expecting to announce preliminary results shortly after polls close at 7pm (5am Monday AEDT).
The latest opinion polls indicated pro-Donald Trump Jansa's Slovenian Democratic Party (SDS) and Golob's Freedom Movement (GS) were set for a close race after an 11th-hour campaign drama involving allegations of foreign meddling and graft.
Jansa said the vote was one of the most important in Slovenia's 35 years of independence, and would decide the future direction of the country.
"I hope that Slovenia will get rid of the organised criminal organisation," he told reporters after casting his vote in the village of Arnace, 85km northwest of the capital Ljubljana.
Analysts say Jansa, who is seeking a fourth term as premier of the European Union and NATO member state of two million people, has a devoted voter base and the lower the turnout, the higher the chances of him winning the election.
At stake is Slovenia's domestic and foreign agenda, where the outgoing government had focused on social and health reforms but delivered mixed results.
Jansa has promised to introduce tax breaks for businesses and cut funding for civil society, welfare and media.
Pro-Israeli Jansa, who is an ally of Hungary's veteran nationalist leader Viktor Orban, would also likely change Golob's foreign policy, under which Slovenia was one of the few European countries that recognised an independent Palestinian state and imposed an arms embargo on Israel in 2025.
The election campaign, which observers described as dirty from the start, heated up in March when covert videos were published on an anonymous website purportedly exposing government corruption.
A report this week alleged Jansa met with officials from Israeli private spy firm Black Cube, which LinkedIn alleged in 2023 was behind a hidden camera campaign that targeted activists and journalists in the lead-up to Hungary's 2022 vote.
Ifigenija Simonovic, a 73-year-old writer, said she did not like the language and rudeness seen in the election campaign.
"No politeness, some lies that came out on one side or the other, so I didn't feel they were telling us, the voters, the story that we could follow," Simonovic said after casting her vote in Ljubljana.
"So to decide today it really wasn't easy."
