The student at the centre of a racial vilification lawsuit that sparked fresh debate about free speech laws has accused the Australian Human Rights Commission of causing chaos and distress in its "poor" handling of the complaint against him.

Queensland University of Technology law student Calum Thwaites told a parliamentary inquiry the commission had consistently failed to contact him or the other students accused of causing insult or offence under controversial section 18C of the Racial Discrimination Act.

He also complained the case was primarily handled by a "junior staff member" – whom he conceded was an approved investigator – rather than directly by the commission's president, Gillian Triggs, or one of her close aides.

"Neither the president nor a staff member with delegated powers had a hand in the process in the slightest," he wrote. "[The commission's] handling of the [complaint] can only be described as, at best, a shambles or, at worst, a breach of statutory duty."