By
Lines formed outside several polling stations visited by AFP as voters waited for the doors to open at 7:00 am (0500 GMT), despite the early winter chill.
The ruling African National Congress has swept every election since the first all-race elections in 1994 ended white-minority apartheid rule.
The party of Nelson Mandela is expected to easily win again in most parts of the country, but opinion polls suggest that the ANC may take a smaller margin of victory as the opposition Democratic Alliances makes inroads.