World Cup organisers on Tuesday urged fans to leave early for the tournament's June 11 kick-off, saying they feared a "nightmare" traffic situation following two dress rehearsal matches.
Jerome Valcke, general secretary of football governing body FIFA, said fans should arrive at least an hour early for the 2 pm (1200 GMT) opening ceremony ahead of the tournament's first match between South Africa and Mexico.
"We must and we have to start this World Cup with a full stadium. It would be sad if the stadium is (only) full by the time Bafana Bafana already scored two goals against Mexico," Valcke told reporters following the final pre-World Cup meeting of South Africa's organising committee.
Highways leading to the 94,700-seat Soccer City, venue for the opening and final matches, were jammed with more than five kilometres (three miles) of traffic Thursday as fans made their way to a friendly between the national team and Colombia.
The bottleneck was a repeat of the previous Saturday's Nedbank Cup final, the stadium's first professional match, which was delayed by half an hour because of traffic.
"After the Nedbank Cup final we immediately asked for a meeting with all the people involved in the municipality and the province," Valcke said.
"The plan we got was, I have to say, a good plan," he added.
Johannesburg officials said Friday that private cars would be blocked from World Cup stadiums to ease traffic. To get inside the 800-metre (half-mile) security perimetre around stadiums, fans will have to take park-and-ride buses or enter on foot.
Valcke said organisers were also trying to arrange for Soccer City to open four hours ahead of the opening ceremony instead of two.