Correctional Services spokesman Manelisi Wolela has denied allegations that student leader Mcebo Dla.
Blade Nzimande, general secretary of the South African Communist Party, has called for a thorough scrutiny of politicians.
He said this would ensure that they are "not politicians by day" and "businesspeople by night".
Nzimande said such scrutiny was the only way of ridding South Africa of corruption.
Speaking at the Young Communist League's second national congress in Durban yesterday, Nzimande lashed out at politicians who used their positions to get ahead in business.
"It is noticeable that such politicians use their positions to gain access to business opportunities in the private sector, or the state sector in the form of tenders."
He said one of the most serious threats to the country's national democratic revolution was corruption.
"We expect you, as young communists, to play a prominent role in intensifying the struggle against corruption," said Nzimande.
He said that to save South Africa from "parasitic capitalism" the struggle against corruption would have to be incorporated into all the campaigns of the party and of the league.
"If there is one cancer other than Aids that is threatening to steal the future of our youth, it is corruption."
The congress, at the Mangosuthu Technikon in Umlazi, south of Durban, is expected to end on Sunday.
Jacob Zuma, the ANC's deputy president, and Zwelinzima Vavi, Cosatu's general secretary, are scheduled to speak at the congress today.