Trade union federation Fedusa announced on Thursday morning that it had placed its General Secretary, Dennis George, on precautionary suspension.
George had been placed on special leave on February 6.
"This decision comes in the wake of allegations relating to the acquisition of shares in technology company, AYO Technology Systems," said the federation.
"In remaining steadfast to the principles of accountability, and the continued promotion of good, clean, ethical governance, Fedusa initiated an independent, external investigation to determine the veracity of the allegations. The investigation remains ongoing."
George previously denied any wrongdoing to Fin24 after he was placed on special leave, saying he was only facing "allegations" and had already answered questions put to him by the federation.
"I have answered some of the questions I have been asked… they [Fedusa] have a right to conduct the investigation as required by the law. But I must state these are just allegations. They are baseless," he said on February 6.
AYO Technology Solutions has been under the spotlight at the judicial commission of inquiry into state-run asset manager the Public Investment Corporation. George is an independent member of the AYO board.
Earlier in the week the Companies and Intellectual Property Commission ordered the PIC to recoup its R4.3bn investment in the company.