Charities and church groups in South Africa are raising the alarm over the threat of child trafficking during the World Cup.

The tournament is expected to draw as many as 500,000 visitors from all over the world. Authorities are warning that predators masquerading as soccer fans will be on the prowl during the event.

The Southern African Catholic Bishops' Conference said it was concerned that the tournament could lead to an "increase in the abuse, exploitation and trafficking in persons especially children" as "abusers" try to meet increased demand in the local sex trade during the games.

World Vision also issued a statement Thursday, cautioning that the tournament will bring a "heightened risk" of child exploitation and trafficking due in part to a lack of legal protections.

The country's anti-trafficking laws "are all fragmented and do not adequately address prevention, protection and prosecution, especially as it relates to safeguarding the rights and dignity of children," the statement said.

South Africa has become a major hub for human trafficking, where an estimated 40,000 children have been lured into prostitution and slavery.

CTV's Lisa LaFlamme spoke to one of them, 15-year-old Maggie, who was able to escape after she was captured.

"There was this other guy looking good, then came to me and was like "I'm looking for people who want to do modeling,'" she recalled in Soweto, an impoverished Johannesburg neighbourhood. "I said 'okay, I'm good for modeling and I can do it.'"

To prevent such incidents a number of charitable groups are setting up a "child-friendly," supervised space at Elkah Stadium in Soweto.

Others have started handing out red cards to children, which are designed to raise awareness about exploitation and to help them ward off potential kidnappers.

Meanwhile, government officials have admitted that country's anti-trafficking laws may not be enough.

"Law enforcement is looking into it," said Faith Hadebe with the human trafficking task force. "We may be a bit late because the World Cup is here now."

Last month, President Jacob Zuma warned South Africans to be vigilant in order to protect the country's younger generation.

"Children wandering alone in shopping malls and football stadiums will be vulnerable to people with evil intentions," he said. "We will play our part as government but parents and caregivers also have to be vigilant."

With a report from CTV's Lisa LaFlamme