FIFA Secretary-General Jerome Valcke said revised seating plans and allocations had created the extra spaces and the percentage of seats sold could be slightly higher than at the finals in Germany four years ago.
Valcke had previously said total seats at the World Cup, starting on June 11 in Johannesburg, would be 2.88 million.
"We are getting closer and closer to the best World Cup ever in terms of ticketing which was USA in 1994," he told a news conference. "It is an amazing result that we have in South Africa."
In April, football authorities launched a drive to sell the remaining 500,000 tickets for Africa's first World Cup by allowing cash sales over the counter rather than the previous internet-only system, which Valcke acknowledged was a mistake in a developing country.
The move not only provoked a scramble for tickets but finally ignited huge excitement over the tournament in a country which FIFA, world football's governing body, last year accused of being apathetic.
Valcke strongly criticised FIFA's official ticketing agency, MATCH, for the collapse of its computer system under the strain when a final tranche of 90,000 tickets went on sale last Friday.
"I was very, very disappointed when the system went down....I felt very bad. It is really not very professional I have to say. Definitely I think it was wrong," Valcke said in unusually strong criticism of MATCH.
TRAFFIC CONCERNS
Valcke also said there were concerns over traffic problems around the giant Soccer City showpiece stadium for the opening ceremony on June 11, after major congestion delayed spectators at recent rugby and football matches in the area.
He said it was "amazing" how late South Africans came to matches and there could be a nightmare situation on June 11 unless spectators arrived early, with the security convoys of 50 heads of state expected to add to the problems.
"We must start this World Cup with a full stadium," Valcke said.
He appealed for fans to be seated by 1pm (11am GMT), an hour before the ceremony is due to begin.
Asked about a recent South African press report saying there was a very high chance of a terrorist attack at the World Cup, Valcke said: "We have to trust the system we have... We know that the South African police have done their best to ensure the highest security level."
He said local police would be supported by forces from all the 31 other competing nations and that the USA-England match on June 12, which has been identified as a potential target, would be the best protected match in the tournament.
