Tunisian President Moncef Marzouki, standing for re-election, cast his vote in the country's first direct presidential election since the 2011 revolution that ended the regime of Zine el-Abidine Ben Ali.

Nearly 30 presidential candidates are running but the Nidaa Tounes leader, Beji Caid Essebsi, an 87-year-old former Ben Ali official, has emerged as a frontrunner alongside the current president, Moncef Marzouki, who warns against the rise of one-party era figures like Essebsi.

Today's vote follows the general election in October when the main secular Nidaa Tounes party won the most seats in the parliament, beating the Islamist party Ennahda that had won the first free poll in 2011.

Leader of the Ennahda party Rached Ghannounchi, who cast his vote in Tunis, said it was a historical day for the country.

Results will be released within 48 hours. But most analysts predict neither Essebsi nor Marzouki will win enough votes to avoid a second round of voting in December.