South Africa has spent 17 billion rands (2.27 billion U.S. dollars) upgrading 10 airports for the FIFA 2010 World Cup, and the number of flights for the period on the tournament had almost doubled, Airports Company South Africa (ACSA) said on Tuesday.

Addressing the media at a press conference to mark the 100 days to kick off on June 11, ACSA's group manager of operations Andre Vermeulen said an extra 120,000 flights have been allocated over the World Cup period. Even more slots were still available if needed, he said.

Vermeulen told reporters there had been an increase in the number of requests for more slots in June and July by commercial and non-commercial airlines.

The number of flights over the World Cup period had almost doubled in relation to other times of the year, he explained.

The country's biggest airport, OR Tambo International Airport outside Johannesburg, currently had about 45 to 46 incoming and outgoing flights an hour, and could handle 60.

OR Tambo airport's general manager Chris Hlekane, speaking on behalf of the 10 airports which would host World Cup fans, said that with 100 days to go their reonovations and upgrades were 90 percent complete.

All major projects at OR Tambo International had been completed and were being fine-tuned.

The South African Press Association (SAPA) reported that at Cape Town International, the departures level was 80 percent complete. The reconfiguration and upgrading of access roads, the multi-story parkade and the central terminal building in Cape Town would be completed in March.

Durban's King Shaka International airport would be completed in April and operational in May. The total cost of the upgrades and renovations of the 10 airports was 2.27 billion U.S dollars.

"We have now entered a critical stage. We will continue with our partners to ensure that the operational plans are completed within the next couple of weeks," said Hlekane.

Last year South Africa hosted the much smaller FIFA Confederations Cup. Hlekane said that during that exercise public transport access to the airport had been highlighted as a problem.

Because of this, bus transport and possible tour operator licenses would be available to ease congestion during the World Cup.

Hlekane said negotiations with South African unions and the South African labor department on extended working hours for employees were also in the final stages.

OR Tambo, Cape Town, King Shaka, Bloemfontein, Port Elizabeth and George airports would operate 24 hours a day for the first two weeks of the World Cup, according to SAPA.

The tournament runs from June 11 to July 11.

ACSA spokesman Solomon Makgale said the company relationship with South Africa National Education, Health and Allied Workers' Union was excellent and the authority was not aware of any industrial action over the period.