Gautrain faces possible court action after a man dressed in traditional Ndebele garb was not allowed to board a train more than a week ago because he was not dressed "appropriately".
Thando Mahlangu was asked to leave the operator's Park Station in Johannesburg.
His lawyer, Benny Buthelezi, told Talk Radio 702's Bongani Bingwa on Thursday that Mahlangu had been humiliated.
He added that "it is a point that needs to be ventilated at the highest level in-country".
During the interview, Buthelezi also accused Gautrain's top management of failing to deal with the issue and of supporting its security guards' decision to bar Mahlangu from boarding a train.Mahlangu also wants compensation, claiming that he lost money he could have made from a business meeting he couldn't attend.
Gautrain CEO Jack van der Merwe told the radio station that he had apologised to Mahlangu.
But Buthelezi claims that the apology was only made through the media and social media.
Gauteng's Transport MEC Ismael Vadi also weighed in on the matter and said it was unacceptable that the 34-year-old was turned away simply because of what he was wearing.