Johannesburg - Parliament's joint standing committee on intelligence (JSCI) must probe reports that state resources were abused by the special operations unit of the State Security Agency, the DA said on Sunday.
"There is yet no telling just how far this rogue element extends into South Africa's security apparatus," Democratic Alliance MP Dirk Stubbe said in a statement.
"If we do not stop this now, we will allow our country to return to the days where the security services became a state within a state, feared by the people, and outside of civilian control."
He said this might become a threat to the country's constitution and democracy.
The DA would request the JSCI to launch a full investigation.
City Press reported on Sunday that people were allegedly working as spies for the unit of the SSA.
The unit, which reportedly operated from a house in Pretoria east, had worked with alleged tobacco smugglers, which the SA Revenue Service was trying to clamp down on. Convicted drug trafficker Glen Agliotti who testified against former national police commissioner Jackie Selebi allegedly recruited the smugglers.
The group also allegedly had a hand in trying to reinstate former crime intelligence boss Richard Mdluli and the ousting of former NPA prosecutor Glynnis Breytenbach, and replacing Sars top management.