Ali Ben Bongo is on course to follow in his father’s footsteps and become President of Gabon.
He reportedly has a commanding lead in the presidential election and is well ahead of ex-interior minister Andre Mba Obame.
Just over 800,000 voters were registered to take part in the central African nation’s election following the death of Omar Bongo.
His fatal heart attack in June ended his nearly 42 year reign of power.
Security forces earlier used tear gas to disperse hundreds of opposition supporters who had led an overnight sit-in near the election commission.
Ben Bongo’s rivals fear the results will be rigged to ensure a dynastic succession.