Correctional Services spokesman Manelisi Wolela has denied allegations that student leader Mcebo Dla.
SOUTH African Airways workers are picketing daily to force acting CEO Chris Smyth to apologise for allegedly calling shop stewards who had gathered in his office "f... kaffirs".
It is alleged that the workers went to Smyth's office last week to insist that management address their demands.
"Workers had earlier met the general manager Bhabhalazi Bulunga and he could not help with matters they had raised," said SA Transport Workers' Union (Satawu) Gauteng secretary Ephraim Mphahlele.
Mphahlele alleged that 15 union leaders then went to Smyth's office and while they were waiting for him at reception he came out of his office and told workers "get out of my office you f.... kaffirs".
Mphahlele said Smyth was given until last Tuesday to apologise for the racial slur but he refused.
"We are going to picket every day until he apologises," said Mphahlele.
He said the next possible action would be to demand that he be sacked.
Bulunga denied that he had heard Smyth "speaking those words".
SAA spokesperson Robyn Chalmers said Smyth had denied the allegation.
"This did not happen. What did happen was that several Satawu shop stewards barged into his offices and behaved in a disorderly fashion," Chalmers said.
"In response to the rowdiness of the situation, he loudly instructed the Satawu individuals to leave his office immediately. At no stage did he utter any racial insult to anybody."
Police spokesperson Senior Superintendent Tummi Golding confirmed that Satawu had opened a case of crimen injuria.
Smyth had given police a written affidavit that he did not utter any racial insults.
Bulunga has also given a written affidavit confirming that he was present and Smyth did not utter the racial insult.