Radio 702 said its reporters had managed for three months to get knives, razor blades, screwdrivers and syringes through security at Johannesburg and other tournament host airports.
ACSA, the airports firm that is responsible for security checks, said it was looking into the allegations and would tighten its procedures. It was confident fans would be safe.
Meanwhile, police paraded through the streets of Johannesburg's smart Sandton business district with a convoy of dozens of vehicles and staged mock operations by elite security forces, including a helicopter drop of commandos onto a car hijack and abseiling down the side of a media building.
Officials said in a statement the demonstration was to "reassure millions of fans that South Africa is more than ready to effectively police" the World Cup.
Security and crime have been one of the biggest issues ahead of the World Cup because of South Africa's notorious reputation for violent offences - it has 50 murders a day, almost the same rate as the United States with six times the population.
But Police Minister Nathi Mthetwa said foreign visitors should remain vigilant. "We are aware that criminals may want to take advantage... we urge them (tourists) to exercise caution."
The parade included everything from helicopters and anti-hijack vans to police cars, fire engines, paramedic vehicles, heavy riot trucks and - rather incongruously considering Johannesburg is at least 550 km from the sea - a divers' dinghy.
People watching the parade seemed convinced. "So far so good. It's really looking good from the whole performance and parade here. I am very confident that we are going to be okay," said Lynette Lubbe, a young woman watching the show.
